Answer:
140 degrees
Step-by-step explanation:
Because angle ABC is a right angle (90°), we got an equation: x + 10° = 90°
x + 10° = 90°
x = 90° - 10°
x = 80°
Angle DCB is: 2 x 80° - 20° = 140°
Also angle BAD is a right angle (90°)
Because the total sum of interior angles of a quadrilateral is 360°, that means angle ADC equals: 360° - (90° + 90° + 140°) = 40°
Because ∠ADC + ∠ADE = 180°, angle ADE equals: 180° - 40° = 140°
