Question

24.Three angles of a quadrilateral are 120 deg, 80 deg, 75 deg.Then the fourth angle is *​

Answer 1

Answer:

We know that, sum of all the 1 angles of a quadrilateral is 360°. Hence, the fourth angle of a quadrilateral is 120°.

Answer 2

Required Answer :

Fourth angle of quadrilateral = 85°

Given :

• Angles of a quadrilateral :

• First angle = 120°
• Second angle = 80°
• Third angle = 75°

To find :

• Fourth angle of quadrilateral

Solution :

Using formula,

• Sum of interior angles of a polygon = (2n - 4) × 90°

where,

• n denotes the number of sides

A quadrilateral has 4 angles, 4 sides.

⇒ Number of sides (n) = 4

Let,

• The fourth angle of quadrilateral = x

Substituting the given values :

⇒ 120° + 80° + 75° + x = (2(4) - 4) × 90°

⇒ 275° + x = (8 - 4) × 90°

⇒ 275° + x = (4) × 90°

⇒ 275° + x = 360°

⇒ x = 360° - 275°

⇒ x = 85°

⇒ The value of x = 85°

Substituting the value of x :

⇒ Fourth angle of quadrilateral = x

⇒ Fourth angle of quadrilateral = 85°