Question

In triangle ABC, angle B =90° nd angle C=theta. If tan thetha =3/4 then find the value of cos (90°- thetha)

Answer 1

★Answer:-

Α

|\

| \

| \

3cm | \

| \

| \

| \

| \

|_ _ _ _ θ \

Β 4cm C

Using Pythagoras theorem

(hypotenuse)² = (side)² + (side)²

AC² = AB² + BC²

AC² = 3² + 4²

AC² = 9 + 16

AC² = 25

AC = √25

AC = 5

TO FIND:

cos(90° - θ) = sinθ

Because 90 is odd multiple of 90.So, the trigonometric ratio will changeand 90 minus theta is is first quadrant and all the trigonometric ratios are positive in quadrant 1

Now,

sinθ = opposite/hypotenuse

sinθ = 3/5