Question

if sin theta = 20/29 then find cos theta​

Answer 1

Answer:

sin = perpendicular /hypotenuse

therefore p=20,h=29

By Pythagoras theorem

H2=P2+B2

29*29=20*20+B2

B2=841-400

B=√441

B=21

cos= Base/hypotenuse

cos theta =21/29

Answer 2

Given: sin theta = 20/29

To find: The value of cos theta​.

Solution:

The sine of the acute angle of a right-angled triangle is calculated using the following formula.

$sin \theta = \frac{perpendicular}{hypotenuse}$

       $= \frac{20}{29}$

This means that the perpendicular is 20 units and the hypotenuse is 29 units in length. Now, the cosine of the acute angle of a right-angled triangle is calculated using the following formula.

$cos \theta = \frac{base}{hypotenuse}$

Since the perpendicular and the hypotenuse is identified, the base can be calculated using the Pythagoras Theorem.

$base = \sqrt{29^{2} - 20^{2}}$

       $= \sqrt{441}$

       $=21$

Thus, the cosine of the angle is

$cos \theta = \frac{21}{29}$

Therefore, the value of cos theta​ is 21/29.