**Contents**show

## Why is sin 90 a cosa?

Triangles! … All triangles have 3 angles that add to 180 degrees. Therefore, if one angle is 90 degrees we can figure out Sin Theta **= Cos** (90 – Theta) and Cos Theta = Sin (90 – Theta).

## Can you use sin 90 in law of sines?

The short answer is that **you can’t construct a right angle triangle to visualise sin90∘**. The “opposite” (or “perpendicular” as per your nomenclature) side has to be distinct from the hypotenuse, it cannot be the same side.

## Is sin 90 a cosa?

sin (90 – a) = **sin 90**. cos a – sin a cos 90.

## What is sin 180 A?

The exact value of sin 180 is **zero**. Sine is known to be one of the primary trigonometric functions which help in determining the angle or sides of a right-angled triangle. It is also called trigonometric ratio.

## Is Cos 90 a equal to sin a?

∴cos(90∘−a)**=sina** .