Question

7. In quadrilateral ABCD, C = 64°, D = 20 - 8°; A = 5(a + 2)° and
B = 2(2a + 7).calculate a​

Answer 1

Answer:

∵ ∠C = 64° (Given)

∴ ∠D = ∠C - 8°

=  64°- 8°

= 56°

∠A = 5 (a + 2)°

∠B = 2(2a + 7)°

Now ∠A + ∠B + ∠C + ∠D = 360°

5(a + 2)° + 2(2a + 7)° + 64°+ 56° = 360°

5a + 10 + 4a + 14° + 64° + 56° = 360°

9a + 144° = 360°

9a = 360° - 144°

9a = 216°

a = 24°

∴ ∠A = 5(a + 2)

= 5(24 + 2)

= 130°