In the given figure : ∠b = 2a + 15 and ∠c = 3a + 5; find the values of b and c.
Answer
Stun of angles of quadrilateral = 360°
70° + a + 2a + 15 + 3a + 5 = 360°
⇒ 6a + 90° = 360°
⇒ 6a = 270°
⇒ a = 45°
b = 2a + 15 = 2×45 + 15 = 105°
c = 3a + 5 = 3×45 + 5 = 140°
Hence ∠b and ∠c are 105° and 140°