Question

in the given figure triangle ABC is equal to 70 degree and triangle ADB is equal to 30 degree.Then find the value of triangle BCD

Answer 1

DBC=30°bcz alternative interior angle
DBC=70°bcz of alternative interior angle
sum of triangle=180°
30°+70°+x=180°
100°+x=180°
x=80°

Answer 2

Answer:

∠BCD = 100°.

Step-by-step explanation:

Given information: ∠ABC = 70° and ∠ADB = 30°.

According to the angle sum property, the sum of interior angles of a triangle is 180°.

In triangle ABD,

$\angle ABD+\angle BDA+\angle  BAD=180^{\circ}$

$70^{\circ}+30^{\circ}+\angle  BAD=180^{\circ}$

$100^{\circ}+\angle  BAD=180^{\circ}$

$\angle  BAD=180^{\circ}-100^{\circ}$

$\angle  BAD=80^{\circ}$

In a circle the opposite angles of a cyclic quadrilateral are supplementary.

$\angle BAD+\angle BCD=180^{\circ}$

$80^{\circ}+\angle BCD=180^{\circ}$

$\angle BCD=180^{\circ}-80^{\circ}$

$\angle BCD=100^{\circ}$

Therefore, the measure of angle BCD is 100°.