Question

In scalene triangle ABC shown in the diagram

below, mC = 90°.

Which equation is always true?
A) cos A = cos B
B) cos A = sin C
C) sin A=sin B
D) sin A = cos B

Answer 1

for given Triangle

sin A = cos B is always

Costuet

Hence option d is career

Explanation:

`given\ \ \ \ \ < C=90\textdegree`

`In\ \Delta\ ABC;\ \ \ \ \ < A+ < B+ < C=180`

`A+B=180-C`

`A+B=180-90=90`

`A=90-B`

`taking\ sine\ on\ noth\ side`

`sin\ A=sin(90-B)\\ sin\ A=cos\ B`

`Henee\ ophon\ 'd'\ is\ cgrrect.`

I hope this helps you

:)