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Explore the geometric mean, Pythagorean Theorem, and triangle properties such as obtuse, acute, and 45-45-90 triangles. Learn about sine, cosine, and tangent ratios for right triangles.
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Geometry Chapter 8 Review
Geometric Mean Find the geometric mean between the two numbers. • 5 and 20 • 64 and 49
Corollary 1 piece of hypotenuse altitude altitude other piece of hypotenuse = Y X A Z
Corollary 2 hypotenuse leg leg piece of hyp. adj. to leg = Y X A Z
Corollary 2 hypotenuse leg leg piece of hyp. adj. to leg = Y X A Z
Pythagorean Theorem • In a right triangle, the square of the hypotenuse is equal to the sum of the squares of the legs. A c b C a B
Theorem: Converse of the Pythagorean Theorem If the square of one side of a triangle is equal to the sum of the squares of the other two sides, then the triangle is a right triangle. If c² = a² + b² Rt. ∆ c b a
Theorem If the square of the longest side of a triangle is greater than the sum of the squares of the other two sides, then the triangle is an obtuse triangle. If c² > a² + b² Obtuse ∆ c b obtuse a
Theorem If the square of the longest side of a triangle is less than the sum of the squares of the other two sides, then the triangle is an acute triangle. If c² < a² + b² Acute ∆ c b acute a
45-45-90 Triangles The formula. o 45 x o 45 x Since all 45-45-90 triangles are similar, by AA Similarity Postulate, this formula works for all 45-45-90 triangles.
30-60-90 Triangles The formula. o 30 2x o 60 x Since all 30-60-90 triangles are similar, by AA Similarity Postulate, this formula works for all 30-60-90 triangles.
Tangent ratio= The tangent ratio is the ratio of the length of the legs in a Rt. ∆ opposite leg hypotenuse Tangent of <A: A adjacent leg
Sine and Cosine Ratios The sine ratio is the ratio of the length of the legs in a Rt. ∆ opposite leg hypotenuse Sine of <A: A adjacent leg opposite leg hypotenuse Cosine of <A: A adjacent leg
HW • W.S. Let’s do the odds on Chapter 8 side together!