Question

the measure of 3 angles of a quadrilateral are 30°
70° and 100°, find the fourth angle.​

Answer 1

Answer:

4 angles are equivalent to 360

taking this property in mind we will sum up all the first 3 that are given. here lets make a equation on this and solve it

30 + 70 + 100 + x = 360

200 + x = 360

x = 360 - 200

x = 160

means the 4th angle is 160

Answer 2

Given:

• Measure of 3 angles in a quadrilateral = 30°, 70°, 100°

To find:

1. Find the 4th angle.

Method:

Let the Forth angle be x

By Angle Sum Property,

The Sum of all angles in a Quadrilateral is 360°

30° + 70° + 100° + x = 360°

⇒ 100° + 100° + x = 360°

⇒ 200° + x = 360°

⇒ x = 360° - 200°

⇒ x = 160°

Therefore the forth angle in the quadrilateral is 160°

Additional information:

1. A rectangle consists of 2 triangles.
2. We know that sum of all angles in a Triangle is 180°
3. Since there are 2 triangles, the sum of all the given angles will be equal to 2 × 180° = 360°