Question

Find the value of x. Please give full explanation

Answer 1

Here is your solution,

Let the upper triangle be ABC and lower triangle be DBC

∠A = 100°

∠ABD = x°

∠BCD = 50°

AB = AC (given)

So, ∠ABC = ∠ACB

Let ∠ABC = ∠ACB = ∠1

In ΔABC,

∠A+∠B+∠C = 180°

100°+∠1+∠1 = 180°

2∠1 = 180-100

2∠1 = 80°

∠1 = 80/2

∠1 = 40°

∠ABC = 40°

In ΔDBC,

DB = DC (given)

∠DBC = ∠DCB

So, ∠DBC = 50°

∠x = ∠ABC+∠DBC

∠x = 40°+50°

∠x = 90°

Hope it helped and please mark my answer as brainliest.