Angle Sum

Slide 1 : TRIANGLES In any triangle, sum of the interior angles is equal to 1800 B A C ∟A + ∟B + ∟C = 1800

Slide 2 : Angle Sum of a Triangle Verification: A straight angle is 180 degrees Hence angle sum of a triangle is 180 degrees

Slide 3 : Angle Sum of a Triangle Calculate the size of the missing angle in the triangle. Solution: Let the missing angle be x So, the missing angle = 840

Slide 4 : Angle sum of a quadrilateral A B C D Draw a quadrilateral ABCD.  Then draw the diagonal AC to form two triangles. Angle sum of a quadrilateral = 2 x 1800 = 3600

Slide 5 : QUADRILATERALS Find the value of the missing angles in the following diagram.  Give reasons for your answer. Solution: x + 68 +126+ 106 = 360 (Angle sum of a quadrilateral is 1800) x + 300 = 360 x = 360 - 300 = 60 x = 600