Answer:
x = 54°
Step-by-step explanation:
(5-2)·180° = 540°, which is the total amount of degrees inside a pentagon
if it's regular then each angle is equal so m∡B = 540/5 or 108°
∠DBC ≅ ∠CDB because ΔCBD is isosceles
half of 108 is 54°
