Question

Find x in the triangle, work it out
.

Answer 1

Explanation:

In ΔABC ,

∠A + ∠B + ∠C = 180 {Angle sum property of triangle}

90 + ∠B + 64 = 180

∠B + 154 = 180

∠B = 180 - 154

∠B = 26

AD = BD

So, ∠1 = ∠3 {Angles opposite to equal sides are equal}

∠1 = ∠3 = 26

In ΔADB

∠1 + ∠2 + ∠3 = 180

26 + ∠2 + 26 = 180

∠2 + 52 = 180

∠2 = 180 - 52

∠2 = 128

15x - 7 = 128

15x = 128 + 7

15x = 135

x = 135/15

x = 9