We know, the amount of the angles of a triangle = 180° since there are two triangles, therefore, the amount of two triangles is 180° + 180° = 360°

Note: The amount of the 4 angles is 360°.

You are watching: What is the sum of angles in a quadrilateral

For Example:1. In a quadrilateral ABCD, ∠A = 100°, ∠B = 105° and also ∠C = 70°, find ∠D.Solution: Here the amount of the 4 angles or, ∠A + ∠B + ∠C + ∠D = 360°We know, ∠A = 100°, ∠B = 105° and also ∠C = 70°or, 100° + 105° + 70° + ∠D = 360°or, 275° + ∠D = 360°∠D = 360° - 275° Therefore, ∠D = 85°

2. uncover the measure of the absent angles in a parallelogram, if ∠A = 70°.

Solution:We understand the opposite angles of a parallelogram room equal.So, ∠C will likewise measure 70°Sum of angle = 360°∠A + ∠B + ∠C + ∠D = 360°or, 70° + ∠B + 70° + ∠D = 360° (We know, ∠A = ∠C )or, ∠B + ∠D + 140° = 360°or, ∠B + ∠D = 360° - 140° or, ∠B + ∠D = 220°But ∠B = ∠D (Because opposites angle of a parallelogram room equal)∠B = ∠D = 220° ÷ 2 = 110° Therefore, ∠B = 110°, ∠C = 70° and also ∠ D = 110°

Parallel Lines.

Perpendicular Lines.

Construction the Perpendicular present by using a Protractor.

Sum of angles of a Quadrilateral.

Have your say about what you just read! leaving me a comment in the box below. Questioning a concern or prize a Question.

See more: What Region Of North America Is Most Densely Populated Region Of North America?

Didn"t find what you were looking for? Or desire to know much more informationabout Math just Math.Use this Google find to uncover what you need.