Answer:
we have to consider a triangle whose acute angle measure is 45° so that the sine and cosine ratios are equal.
Explanation:
We need to consider a right angled triangle such that the measure of one of angle is 90° ,the second angle is 45° and hence the third angle could be found by using the fact that the sum of all the angles is 180°.
Hence we get the third angle measure to be 45°
( ∠1+∠2+∠3=180°
90+45+∠3=180
∠3=180-(90+45)
∠3=45° )
so in the right angled triangle if we use our trignometric identity along either angle 2 or angle 3 we get;
sin 45°=

and cos 45°=

Hence the sine and cosine angle are equal.
So we have to consider a triangle whose acute angle measure is 45° so that the sine and cosine ratios are equal.