Question

In figure, ZABC = 69º and ZABC = 31°, find ZBDC.
(See Lesson-15)​

Answer 1

Answer:

angle D is 80°. hope it's help please mark as brainlist

Answer 2

Given :

• ∠ABC = 69°
• ∠ACB = 31°

To find :

• ∠BDC

According to the question,

➨ ∠ABC + ∠ACB + ∠BAC = 180°

Reason : Angle sum property

➨ 69° + 31° + ∠BAC = 180°

➨ 100° + ∠BAC = 180°

➨ ∠BAC = 180° - 100°

➨ ∠BAC = 80°

➨∠BAC = ∠BDC

Reason : Angle in the same segment

➨ ∠BDC = 80°

So,

• ∠BDC = 80°

_____________________

Theorem :

The angle subtended by an arc of a circle at the centre is doubled the angle made by the same arc at any point of the circumference.

Theorem :

Angle in a semicircle is right angle (90°).