Question

8.If three angles of a quadrilateral are 75°, 105° and 85°, then its fourth angle will be a 800​

Answer 1

Answer:

¡False!

The fourth angle will be 95°.

solution:-

• we know that the sum of all the angles of a quadrilateral is 360 °.

so, 75°+105°+85°+x = 360°

265° + x = 360°

x = 360°- 265°

x = 95°

so, the fourth angle is 95°.

Answer 2

No , value of fourth angle is 95°

Given :

Three angles of a quadrilateral are

• ∠1 = 75°
• ∠2 = 105°
• ∠3 = 85°

To Find :

• Value of fourth angle

Concept Using :

Angle sum property of a quadrilateral

This property states that the sum of all angles of a quadrilateral is 360°.

∠1 + ∠2 + ∠3 + ∠4 = 360°

Solution :

Let assume the fourth angle of a quadrilateral be x.

According to the concept

↬∠1 + ∠2 + ∠3 + ∠4 = 360°

↬75° + 105° + 85° + x = 360°

↬265° + x = 360°

↬x = 360° - 265°

↬x = 95°