Question

ΔABC, m(∡A)=90°,AB/AC=3/4,BC=15cm. Perimetrul este.....

Answer 1

m(∡A)=90°,
AB/AC=3/4⇒ AB=(3×AC):4
fiind triunghi dreptunghic aplicam Teorema lui Pitagora
BC²=AC²+AB²
BC²=AC²+9×AC²/16
225=(16AC²+9AC²)/16
225=25AC²/16
15=5AC/4
⇒AC=12
AB=(3/4)×AC=(3/4)×12=9
AB =9; AC =12  si BC =15
Perimetrul ΔABC=AC + AB + BC = 9 + 12 + 15 = 36 cm