Honors Geometry Warm-up 1/30 Ashwin is watching the Super Bowl on a wide screen TV with dimensions 32” by 18” while Emily is watching it on an old square TV with the same area. What are the dimensions of Emily’s TV? Answer: 24” X 24”

Geometric Mean

Example 1: Find the geometric mean between each pair of numbers. a. 2 and 50 b. 25 and 7

Example 1C: True or False? The geometric mean of two distinct positive numbers can be greater than the average of the two numbers. a, a + n (where n is the difference between the two numbers)

Altitude of a Triangle: Consider the right triangle ABC with altitude drawn from the right angle B to the hypotenuse. Which triangles are similar to the big triangle ABC?

Theorem 7.1

Proportional Sides C D

Theorem 7.2 The measure of an altitude drawn from the vertex of the right triangle of a right triangle to its hypotenuse is the geometric mean between the measures of the two segments of the hypotenuse. Example : BD is the geometric mean of AD and DC

More Proportional Sides

Theorem 7.3 If the alt. is drawn from the vertex of the right angle of a right triangle to its hyp., then the measure of a leg of the triangle is the geometric mean between the measures of the hyp. and the segment of the hyp. adjacent to that leg. Example: AB is the geometric mean of AD and AC; BC is the geometric mean of DC and AC

Example 2: In triangle ABC, BD=6 and AD=27. Find CD.

Example 3: Mrs. Clark is constructing a kite for her son. She has to arrange perpendicularly two support rods, the shorter of which is 27 inches long. If she has to place the short rod 7.25 inches from one end of the long rod in order to form two right triangles with the kite fabric, what is the length of the long rod? Long rod = in

Example 4: Find c and d in triangle JKL.