Chapter 1 7 Notes Find Perimeter Circumference and

Chapter 1. 7 Notes: Find Perimeter, Circumference, and Area

• Perimeter is the distance around a figure. • Circumference is the distance around a circle. • Area is the amount of surface covered by a figure. • Perimeter and circumference are measured in units of length, such as meters (m) and feet (ft). • Area is measured in square units, such as square meters (m 2) and square feet (ft 2).

• Formulas for Perimeter, Area, and Circumference: • Square: – Perimeter (P) = 4 s – Area (A) = s 2 (s = side length) • Rectangle: – Perimeter (P) = 2 L + 2 w – Area (A) = Lw ( L = length, w = width)

• Triangle: – Perimeter (P) = a + b + c a b – Area (A) = ½ bh (for perimeter; side lengths of triangle a, b, c) (for area; b = base, h = height) • Circle: – Circumference ( C) = πd or C = 2πr – Area (A) = πr 2 • Pi (π) is the ratio of a circle’s circumference to its diameter.

Ex. 1: Find the perimeter and area of the rectangular basketball court shown. Ex. 2: Find the perimeter and area of the dining room shown. 12 ft 9 ft

Ex. 3: You are ordering circular cloth patches for your soccer team’s uniforms. Find the approximate circumference and area of the patch shown. Ex. 4: Find the approximate circumference and area of the circular window shown. (d = 18 in)

• Find the area and perimeter of the figure. If necessary, round to the nearest tenth. Ex. 5: 1. 6 cm Ex. 6: Triangle QRS has vertices Q(1, 2), R(4, 6), and S(5, 2). What is the approximate perimeter of triangle QRS?

Ex. 7: Use the diagram below to answer (a) and (b). a. Describe how to find the height from F to EG in the triangle below. b. Find the perimeter and the area of the triangle shown below.

Ex. 8: The base of a triangle is 28 meters. Its area is 308 square meters. Find the height of the triangle. Ex. 9: The base of a triangle is 14 cm. Its area is 42 cm 2. Find the height of the triangle.

Ex. 10: An ice-resurfacing machine is used to smooth the surface of the ice at a skating rink. The machine can resurface about 270 square yards of ice in one minute. About how many minutes does it take the machine to resurface a rectangular skating rink that is 200 feet long and 90 feet wide?