Odpowiedzi

2010-04-07T14:17:51+02:00
Pc=2*Pp+Pb
Pp=13\2 *(5+13)=117
Pb=3*5*13+13*13=195+169=364 cm^2
Pc=2*117+364=598 cm^2
1 2 1
2010-04-07T14:20:00+02:00

a = 13cm , b = 5cm , c = 5cm
h = 13 cm
h1 - wysokość podstawy graniastosłupa czyli trapezu równoramiennego
Mamy
x = [13 - 5] cm :2 = 8 cm :2 = 4 cm
x² + (h1)² = c²
(h1)² = c² - x² = 5² - 4² = 25 - 16 = 9
h1 = √9 = 3
czyli h1 = 3 cm
Pc = 2Pp + Pb
Pp = 0,5*[a+b] *h1 = 0,5 *[13 + 5] cm*3cm = 27 cm²
Pb =[ a +b + 2c ] *h = [13 +5 +2*5] cm * 13 cm =28 cm *13 cm =
= 364 cm²
zatem
Pc = 2*27 cm² + 364 cm² = 54 cm² + 364 cm² = 418 cm²
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