Question

Do the sides 15cm, 20cm and 25cm represent a right angled triangle? ​

bhai me try kerti hu but kese karu smjh nhi aa raha ​

Answer 1

Answer:

it is a right angled triangle if theta=90°

i.e cos90°=0

by law of cosine:

(25)^2=(15)^2+(20)^2+2(15)(20)costheta

625=225+400+600cos theta

625-625=600cos theta

0/600=cos theta

0=cos theta

theta=cos^-1(0)

theta=90°

hence it is a right angled triangle