Inside angles theorem.

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Presentation transcript:

Inside angles theorem

All angles in a triangle sum up to 180˚

Examples:

Find the value for the missing angle:

Exterior angle theorem

Examples: 40⁰ 90⁰ 50⁰ 140⁰ = 50⁰ + 90⁰ 90⁰ = 50⁰ + 40⁰

Examples: 120⁰ = 35⁰ + 85⁰ 85⁰ 35⁰ 60⁰ 145⁰ = 85⁰ + 60⁰ 95⁰ = 35⁰ + 60⁰

Find the value for the indicated angle

Isosceles triangle theorem

If two sides of a triangle are congruent, then the angles opposite to those sides are congruent.

Examples

Find the value OF X: 2x+5 65˚ 83˚ X˚

Find the value of x: 103 m X 2X-10 90

For help with exterior angle theorem, copy the link and watch: https://www.youtube.com/watch?annotation_id=annotation_1632132577&feature=iv&src_vid=eoe8bpowBK4&v=S1C3Z9SbdG4 For help with the sum of the interior angles of a triangle, copy the link and watch: https://www.youtube.com/watch?v=EZ6dOlRQDBo