Question

17. In figure, BAC -859, CA = CB and BD - CD. Find the measure of ZX, Zy and Zz. Give

reasons to support your answer.
A
85°
ب
B
H
V​

Answer 1

x = 10°, y = 10° and z = 160°

Explanation:

Given : m∠BAC = 85°

CA ≅ CB and BD ≅ CD

In the given ΔABC,

Since, CA ≅ CB

Angles opposite to these equal sides will be equal in measure.

m∠BAC ≅ m∠ABC ≅ 85°

Since, sum of interior angles of a triangle = 180°

m∠BAC + m∠ABC + m∠BCA = 180°

85° + 85° + m∠BCA = 180°

m∠BCA = 180° - 170°

m∠BCA = 10°

x = 10°

In ΔBDC,

Since, BD ≅ DC [Given]

Opposite angles to these equal sides will be equal in measure.

Therefore, x° = z° = 10°

Since, x° + y° + z° = 180°

10° + y° + 10° = 180°

y = 180 - 20°

y = 160°