Question

Hello,Please help me!This is my math work
Find the unknown value of a

Answer 1

104°

Explanation:

The sum of interior angles in a pentagon is 540°

107° + 121° + 3a° = 540°

3a° + 228° = 540°

3a° = 540° - 228°

3a° = 312°

a° = 104°