Presentation on theme: "What is the Triangle Inequality Theorem?"— Presentation transcript:
1 What is the Triangle Inequality Theorem? The Triangle Inequality Theorem states thatthe sum ofANY 2 SIDESof a triangle must beGREATER thanthe measure of the 3rd side.
2 Can multiple triangles have the same angle measures? YES! Similar triangles are triangles whose sides are proportionate and the angles are CONGRUENT!
3 Test the Triangle Inequality Theorem Add each pair of sides to see if it is greater than the third side.Try it with 3 cm, 4 cm, & 6 cm3 + 4 = 7 greater than 64 + 6 = 10 greater than 33 + 6 = 9 greater than 4So…Since each two sums are greater than the third,it can be a triangle.
4 Do you really have to test all 3 sides? No.Just add the two shortest sides.They must be greater than the longest side.
5 Summarize our findings on pg. 90 in your book… Let’s answer #7 together to summarize the Triangle Inequality Theorem.Does 7, 8, and 25 make a triangle?Is 7+8 > 25?Summary statement: To form a triangle, the sum of any two sides must be greater than the 3rd side.
6 What is the formula for finding area of a triangle?
8 Solve for missing angle measure. Write an equation to solve for the missing angle measure.
9 Solve for the missing angle measure. Write an equation to solve for x first.Then you can find the missing angle measure.
10 What do you need to know about geometry? G2 – Draw (freehand & w/ tech) geometric shapesG2 - sum of all the angles in a triangleG2 - how to test side lengths to see if they form a triangle.G3 - 2D shapes that result from cross sections of right rectangular prisms & right rectangular pyramids.G4 – area & circumference of a circle; know relationship between Area & Circum.G5 – Angle pairs - supplementary, complementary, vertical, and adjacent anglesG6 – Solve real-world prob with area, volume, surface area of 2D & 3D objects including triangles, quadrilaterals, polygons, cubes, and right prisms.
11 Determine all the unknown measures in the figure. Handouts included. m < Mm < xm < y
12 Triangle Inequality Theorem Could these be the lengths of a triangle?4, 8, 25, 6, 76, 8, 157, 9, 15