ICSE-VIII-Mathematics
16: Understanding Shapes (Including Polygons) Class 8 Maths
- #11Use the information given in the following figure to find the value of x.
Ans : Take A, B, C, D as the vertices of Quadrilateral and BA is produced to E (say).
Since ∠EAD = 70°
∠DAB = 180° - 70° = 110°
[EAB is a straight line and AD stands on it ∠EAD + ∠DAB = 180°]
110° + 80° + 56° + 3x - 6° = 360°
[sum of interior angles of a quadrilateral = 360°]
3x = 360° - 110° - 80° - 56° + 6°
⇒ 3x = 360° - 240° = 120°
⇒ x = 40°