Edugain

Login/Register Edugain for School

• Indonesia

If $\triangle ABC$ is right angled at $C$, find the value of $cos(A+B)$.

1. Home
2. Math
3. All Questions

Answer:

$0$

Step by Step Explanation:

1. We know that sum of the angles of a triangle is $180^\circ$
   $\angle A + \angle B + \angle C = 180^\circ$
2. It is given that angle $C$ is right angle. Replace $\angle C = 90^\circ$ in above equation
   $\implies \angle A + \angle B + 90^\circ = 180^\circ$
   $\implies \angle A + \angle B = 180^\circ - 90^\circ$
   $\implies \angle A + \angle B = 90^\circ$
   
3. Now we know the value of $A + B$, we can find the value of $cos(A+B)$
   $\implies cos(A+B) = cos(90^\circ)$
   $\implies cos(A+B) = 0$

Practice online or create unlimited worksheets on similar questions.

You can reuse this answer
Creative Commons License