An equilateral triangle ABC surmounts a square BCDE. The value of ∠EAB+3∠AEB is:

Correct option is C

Given:

ABC is an equilateral triangle.

∆ ABC surmounts a square BCDE.

Concept and Formula Used:

Sum of all triangles in a triangle = $$180\degree$$​​

Each angle in equilateral triangle = $$60 \degree$$​​

Solution:

In triangle ABE,

∠EBA = 90+60 =150

Then, ∠EBA+∠BAE+∠ABE = $$180 \degree$$​​

150 + ∠EAB+∠AEB= $$180 \degree$$​​

∠EAB+∠AEB= 180 – 150

∠EAB+∠AEB= 30

So, ∠EAB=∠AEB=15° (opposite angles of the equal sides)

∠EAB+3∠AEB=15°+45°=60°