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Unformatted text preview: le are 6, 8, and 10. Find the altitude drawn to the hypotenuse. (A) 2.4 (B) 4.8 (C) 3.4 (D) 3.5 (E) 4.2 4. If the diagonals of a rhombus are represented by 4x and 6x, the area may be represented by (A) 6x (B) 24x (C) 12x (D) 6x2 (E) 12x2 A circle is inscribed in a square whose side is 6. Express the area of the circle in terms of π. (A) 6π (B) 3π (C) 9π (D) 36π (E) 12π 5. 2. 3. www.petersons.com Geometry 203 2. PERIMETER
The perimeter of a figure is the distance around the outside. If you were fencing in an area, the number of feet of fencing you would need is the perimeter. Perimeter is measured in linear units, that is, centimeters, inches, feet, meters, yards, etc. A. Any polygon = sum of all sides P = 9 + 10 + 11 = 30 B. Circle = π · diameter = πd
or 2 · π · radius = 2πr Since 2r = d, these formulas are the same. The perimeter of a circle is called its circumference. C = π · 8 = 8π or C = 2 · π · 4 = 8π The distance covered by a wheel in one revolution is equal to the circumference of the wheel. In making one revolution, every point on the rim comes in contact with the ground. The distance covered is then the same as stretching the rim out into a straight line. The distance covered by this wheel in one revolution is 2 ⋅ π ⋅ 7 = 14 feet. π www.petersons.com 204 Chapter 13 Exercise 2
Work out each problem. Circle the letter that appear before your answer. 1. The area of an equilateral triangle is 16 3 . Find its perimeter. (A) 24 (B) 16 (C) 48 (D) 24 3 (E) 48 3 The hour hand of a clock is 3 feet long. How many feet does the tip of this hand move between 9:30 P.M. and 1:30 A.M. the following day? (A) π (B) 2π (C) 3π (D) 4π (E) 24π If the radius of a circle is increased by 3, the circumference is increased by (A) 3 (B) 3π (C) 6 (D) 6π (E) 4.5 4. The radius of a wheel is 18 inches. Find the number of feet covered by this wheel in 20 revolutions. (A) 360π (B) 360 (C) 720π (D) 720 (E) 60π A square is equal in area to a rectangle whose bas...
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