1 \startsection[reference=seccio:teorema-de-Pitagores, title={Teorema de Pitàgores}]
3 \startsubject[title={Preguntes}]
5 Les figures dels exercicis {\em no} estan a escala i, per tant, els raonaments visuals probablement no funcionin.
7 \startexercici[reference=exer:propi-antic-triangles-rectangles-2, title={triangles rectangles}] Trobeu els costats que falten dels triangles següents.
9 \startitemize[a, columns, three]
13 \starttikzpicture[scale=0.75]
14 \draw [line width=1pt] (0,0)-- (3,0) -- (0,4) -- cycle;
15 \draw (1.5,0) node[anchor=north] {$5 \unit{centi meter}$};
16 \draw (0,2) node[anchor=east] {$12 \unit{centi meter}$};
21 \starttikzpicture[scale=0.75]
22 \draw [line width=1pt] (0,0)-- (-3,0) -- (0,4) -- cycle;
23 \draw (0,2) node[anchor=west] {$1,5 \unit{meter}$};
24 \draw (-1.5,2) node[anchor=south east] {$1,7 \unit{meter}$};
29 \starttikzpicture[scale=0.75]
30 \draw [line width=1pt] (0,0)-- (3,0) -- (0,4) -- cycle;
31 \draw (1.5,0) node[anchor=north] {$20 \unit{kilo meter}$};
32 \draw (0,2) node[anchor=east] {$21 \unit{kilo meter}$};
37 \starttikzpicture[scale=0.75]
38 \draw [line width=1pt] (0,0)-- (-3,0) -- (0,4) -- cycle;
39 \draw (0,2) node[anchor=west] {$35 \unit{deci meter}$};
40 \draw (-1.5,2) node[anchor=south east] {$37 \unit{deci meter}$};
45 \starttikzpicture[scale=0.75]
46 \draw [line width=1pt] (0,0)-- (3,0) -- (0,4) -- cycle;
47 \draw (1.5,0) node[anchor=north] {$2,8 \unit{meter}$};
48 \draw (0,2) node[anchor=east] {$4,5 \unit{meter}$};
53 \starttikzpicture[scale=0.75]
54 \draw [line width=1pt] (0,0)-- (-3,0) -- (0,4) -- cycle;
55 \draw (0,2) node[anchor=west] {$55 \unit{centi meter}$};
56 \draw (-1.5,2) node[anchor=south east] {$73 \unit{centi meter}$};
61 \starttikzpicture[scale=0.75]
62 \draw [line width=1pt] (0,0)-- (3,0) -- (0,4) -- cycle;
63 \draw (1.5,0) node[anchor=north] {$6,3 \unit{meter}$};
64 \draw (0,2) node[anchor=east] {$1,6 \unit{meter}$};
69 \starttikzpicture[scale=0.75]
70 \draw [line width=1pt] (0,0)-- (-3,0) -- (0,4) -- cycle;
71 \draw (0,2) node[anchor=west] {$99 \unit{centi meter}$};
72 \draw (-1.5,2) node[anchor=south east] {$101 \unit{centi meter}$};
77 \starttikzpicture[scale=0.75]
78 \draw [line width=1pt] (0,0)-- (-3,0) -- (0,4) -- cycle;
79 \draw (0,2) node[anchor=west] {$91 \unit{centi meter}$};
80 \draw (-1.5,2) node[anchor=south east] {$109 \unit{centi meter}$};
87 \startexercici[reference=exer:propi-antic-triangles-rectangles-1, title={triangles rectangles}] Trobeu \startitemize[a,text] \item què valen els costats desconeguts, \item l'àrea i \item el perímetre dels triangles següents \stopitemize.
90 \startitemize[a, columns]
94 \starttikzpicture[scale=0.75]
95 \draw [line width=1pt] (0,0)-- (3,0) -- (0,4) -- cycle;
96 \draw (1.5,0) node[anchor=north] {$30 \unit{meter}$};
97 \draw (0,2) node[anchor=east] {$40 \unit{meter}$};
98 \draw (1.5,2) node[anchor=south west] {$a$};
103 \starttikzpicture[scale=0.75]
104 \draw [line width=1pt] (0,0)-- (-6,0) -- (0,2) -- cycle;
105 \draw (-3,0) node[anchor=north] {$6 \unit{centi meter}$};
106 \draw (0,1) node[anchor=west] {$2 \unit{centi meter}$};
107 \draw (-3,1) node[anchor=south east] {$a$};
114 \starttikzpicture[scale=0.75]
115 \draw [line width=1pt] (0,0)-- (3,0) -- (0,4) -- cycle;
116 \draw (1.5,0) node[anchor=north] {$6 \unit{kilo meter}$};
117 \draw (0,2) node[anchor=east] {$b$};
118 \draw (1.5,2) node[anchor=south west] {$10 \unit{kilo meter}$};
123 \starttikzpicture[scale=0.75]
124 \draw [line width=1pt] (0,0)-- (-3,0) -- (0,4) -- cycle;
125 \draw (-1.5,0) node[anchor=north] {$c$};
126 \draw (0,2) node[anchor=west] {$12 \unit{meter}$};
127 \draw (-1.5,2) node[anchor=south east] {$15 \unit{meter}$};
133 \startexercici[reference=exer:teorema-de-Pitagores-diagonals-rectangles, title={diagonals de rectangles}] Trobeu les diagonals d'aquests rectangles.
134 \startitemize[a, columns, three]
138 \draw [line width=1pt] (0,0)-- (3,0) -- (3,2) -- (0,2) -- cycle;
139 \draw (1.5,0) node[anchor=north] {$3 \unit{kilo meter}$};
140 \draw (0,1) node[anchor=west] {$2 \unit{kilo meter}$};
146 \draw [line width=1pt] (0,0)-- (2,0) -- (2,3) -- (0,3) -- cycle;
147 \draw (1,0) node[anchor=north] {$1 \unit{meter}$};
148 \draw (0,1.5) node[anchor=west] {$3 \unit{meter}$};
154 \draw [line width=1pt] (0,0)-- (3,0) -- (3,2) -- (0,2) -- cycle;
155 \draw (1.5,0) node[anchor=north] {$0,4 \unit{meter}$};
156 \draw (0,1) node[anchor=west] {$0,3 \unit{meter}$};
162 \draw [line width=1pt] (0,0)-- (2,0) -- (2,3) -- (0,3) -- cycle;
163 \draw (1,0) node[anchor=north] {$1,4 \unit{centi meter}$};
164 \draw (0,1.5) node[anchor=west] {$2,2 \unit{centi meter}$};
170 \draw [line width=1pt] (0,0)-- (3,0) -- (3,2) -- (0,2) -- cycle;
171 \draw (1.5,0) node[anchor=north] {$7 \unit{meter}$};
172 \draw (0,1) node[anchor=west] {$3 \unit{meter}$};
179 \draw [line width=1pt] (0,0)-- (2,0) -- (2,3) -- (0,3) -- cycle;
180 \draw (1,0) node[anchor=north] {$2 \unit{kilo meter}$};
181 \draw (0,1.5) node[anchor=west] {$6 \unit{kilo meter}$};
187 \startexercici[reference=exer:teorema-de-Pitagores-triangles-isosceles, title={triangles isòsceles i equilàters}] Calculeu l'àrea d'aquests triangles isòsceles i equilàters\footnote{Un triangle isòsceles és aquell que té dos costats iguals i un desigual; un triangle equilàter és aquell que té tots els costats iguals.}.
188 \startitemize[a, columns, three]
193 \draw [line width=1pt] (0,0)-- (2,0) -- (1,3) -- cycle;
194 \draw (1,0) node[anchor=north] {$3,6 \unit{meter}$};
195 % agaf els punt mitjans dels vèrtex corresponent per etiquetar els costats
196 \draw (1.5,1.5) node[anchor=south west] {$4,8 \unit{meter}$};
197 \draw (0.5,1.5) node[anchor=south east] {$4,8 \unit{meter}$};
203 \draw [line width=1pt] (0,0)-- (3,0) -- (1.5,2) -- cycle;
204 \draw (1.5,0) node[anchor=north] {$3 \unit{meter}$};
205 % agaf els punt mitjans dels vèrtex corresponent per etiquetar els costats
206 \draw (2.25,1) node[anchor=south west] {$3 \unit{meter}$};
207 \draw (0.75,1) node[anchor=south east] {$3 \unit{meter}$};
214 \draw [line width=1pt] (0,0)-- (2,0) -- (1,3) -- cycle;
215 \draw (1,0) node[anchor=north] {$2 \unit{meter}$};
216 % agaf els punt mitjans dels vèrtex corresponent per etiquetar els costats
217 \draw (1.5,1.5) node[anchor=south west] {$4 \unit{meter}$};
218 \draw (0.5,1.5) node[anchor=south east] {$4 \unit{meter}$};
224 \draw [line width=1pt] (0,0)-- (3,0) -- (1.5,2) -- cycle;
225 \draw (1.5,0) node[anchor=north] {$10 \unit{meter}$};
226 % agaf els punt mitjans dels vèrtex corresponent per etiquetar els costats
227 \draw (2.25,1) node[anchor=south west] {$10 \unit{meter}$};
228 \draw (0.75,1) node[anchor=south east] {$10 \unit{meter}$};
234 \draw [line width=1pt] (0,0)-- (2,0) -- (1,3) -- cycle;
235 \draw (1,0) node[anchor=north] {$9 \unit{meter}$};
236 % agaf els punt mitjans dels vèrtex corresponent per etiquetar els costats
237 \draw (1.5,1.5) node[anchor=south west] {$11 \unit{meter}$};
238 \draw (0.5,1.5) node[anchor=south east] {$11 \unit{meter}$};
245 \draw [line width=1pt] (0,0)-- (3,0) -- (1.5,2) -- cycle;
246 \draw (1.5,0) node[anchor=north] {$1 \unit{kilo meter}$};
247 % agaf els punt mitjans dels vèrtex corresponent per etiquetar els costats
248 \draw (2.25,1) node[anchor=south west] {$1 \unit{kilo meter}$};
249 \draw (0.75,1) node[anchor=south east] {$1 \unit{kilo meter}$};
257 \startexercici[reference=exer:sense-nom-7, title={triangle equilàter}] Trobeu l'àrea d'un triangle equilàter de 8 \unit{centi meter} de costat.
261 \startexercici[reference=exer:talaiot-30, title={hexàgon regular}] Calculeu l'apotema d'un hexàgon regular de 5 \unit{centi meter} de costat.
264 \startexercici[reference=exer:sense-nom-3, title={cub}] Trobeu la diagonal d'un cub de 10 \unit{centi meter} d'aresta
268 \startexercici[reference=exer:talaiot-29] Determineu, sense dibuixar-lo, si un triangle de costats 7, 8 i 9 \unit{centi meter} és rectangle.
272 \startexercici[reference=exer:propi-antic-8, title={figures compostes}] Trobeu \startitemize[a, text] \item l'àrea i \item el perímetre \stopitemize de les figures següents. Potser sigui necessari aplicar el teorema de Pitàgores per trobar algun costat. Noteu que aquestes figures no estan a escala i, per tant, els raonaments visuals poden no funcionar.
275 \startitemize[a, columns]
276 \item \externalfigure[figs/geometria-teorema-de-pitagores-fig-1.eps][width=1.6in]
277 \item \externalfigure[figs/geometria-teorema-de-pitagores-fig-2.eps][width=1.6in]
278 \item \externalfigure[figs/geometria-teorema-de-pitagores-fig-3.eps][width=2.1in]
279 \item \externalfigure[figs/geometria-teorema-de-pitagores-fig-4.eps][width=2.2in]
280 \item \externalfigure[figs/geometria-teorema-de-pitagores-fig-5.eps][width=1.8in]
281 \item \externalfigure[figs/geometria-teorema-de-pitagores-fig-6.eps][width=2.5in]
290 \startsubject[title={Solucions}]
292 \startitemize[1][distance=0.5cm]
293 \sym{\in[exer:propi-antic-triangles-rectangles-2]} \startitemize[a, text] \item $13 \unit{centi meter}$, \item $8 \unit{meter}$, \item $29 \unit{kilo meter}$, \item $12 \unit{deci meter}$, \item $5,3 \unit{meter}$, \item $48 \unit{centi meter}$, \item $6,5 \unit{meter}$, \item $20 \unit{centi meter}$, \item $60 \unit{centi meter}$ \stopitemize
295 \sym{\in[exer:propi-antic-triangles-rectangles-1]} \startitemize[a, text] \item el costat val $50 \unit{meter}$, el perímetre val $120 \unit{meter}$ i l'àrea val $600 \unit{square meter}$ \item el costat val $6,32 \unit{centi meter}$, el perímetre val $14,32 \unit{centi meter}$ i l'àrea val $6 \unit{square centi meter}$ \item el costat val $8 \unit{kilo meter}$, el perímetre val $24 \unit{kilo meter}$ i l'àrea val $24 \unit{square kilo meter}$ \item el costat val $9 \unit{meter}$, el perímetre val $36 \unit{meter}$ i l'àrea val $54 \unit{square meter}$ \stopitemize
297 \sym{\in[exer:teorema-de-Pitagores-diagonals-rectangles]} \startitemize[a, text] \item $3,6 \unit{kilo meter}$, \item $3,16 \unit{meter}$, \item $0,5 \unit{meter}$, \item $2,6 \unit{centi meter}$, \item $7,6 \unit{meter}$, \item $6,3 \unit{kilo meter}$ \stopitemize
299 \sym{\in[exer:teorema-de-Pitagores-triangles-isosceles]} Aproximadament: \startitemize[a, text] \item $4,44 \unit{meter}$ \item $3,87 \unit{meter}$ \item $10,04 \unit{meter}$ \item $2,60 \unit{meter}$ \item $8,66 \unit{meter}$ \item $0,866 \unit{\kilo \meter}$ \stopitemize
301 \sym{\in[exer:sense-nom-7]} L'àrea fa $27,68 \unit{square centi meter}$
303 \sym{\in[exer:talaiot-30]} L'apotema val $4,33 \unit{centi meter}$
305 \sym{\in[exer:sense-nom-3]} $17,32 \unit{centi meter}$
307 \sym{\in[exer:talaiot-29]} No és un triangle rectangle
309 \sym{\in[exer:propi-antic-8]} \startitemize[a, text] \item $P=19 \unit{centi meter}$, $A=22,8 \unit{square centi meter}$ \item $P=36,66 \unit{centi meter}$, $A=77,42 \unit{square centi meter}$ \item $P=42 \unit{centi meter}$, $A=76 \unit{square centi meter}$ \item $P=36,18 \unit{centi meter}$, $A=50 \unit{square centi meter}$ \item $P=56 \unit{centi meter}$, $A=90,3 \unit{square centi meter}$ \item $P=24,38$, $A=15,82$\stopitemize