The numerical sum of the degree measures of ∠DEA and ∠AEB is 180°.
x = 14.5
m∠DEA = 39.5°
m∠AEB = 140.5°
Solution:
Sum of the measures of adjacent angles in a straight line is 180°.
m∠DEA + m∠AEB = 180°
The numerical sum of the degree measures of ∠DEA and ∠AEB is 180°.
⇒ m∠DEA + m∠AEB = 180°
⇒ (x + 25)° + (9x + 10)° = 180°
⇒ x° + 25° + 9x° + 10° = 180°
⇒ 10x° + 35° = 180°
Subtract 35° from both sides of the equation.
⇒ 10x° = 145°
⇒ x° = 14.5°
⇒ x = 14.5
m∠DEA = (9x + 10)°
= (9(14.5) + 10)°
m∠DEA = 39.5°
m∠AEB = (x + 25)°
= (14.5 + 25)°
m∠AEB = 140.5°