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SECTION 11.1. AREAS of RECTANGLES and SQUARES. WARM UP. Find the area and perimeter of a square that is 5 inches long. The area of a square is 64 cm 2 . What is the perimeter? The perimeter of a square is 28 inches. What is the area?. A = 5 · 5 = 25. P = 5 + 5 + 5 + 5 = 20.
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SECTION 11.1 AREAS of RECTANGLES and SQUARES
WARM UP • Find the area and perimeter of a square that is 5 inches long. • The area of a square is 64 cm2. What is the perimeter? • The perimeter of a square is 28 inches. What is the area? A = 5 · 5 = 25 P = 5 + 5 + 5 + 5 = 20 A = 64, 8 = side P = 8 + 8 + 8 + 8 = 32 cm P = 28, 28/4 = 7 A = 7 · 7 = 49 in2
PERIMETER • TO FIND PERIMETERS • Add all the side lengths together!
Area of SQUARES Area of a square = sides2 = s2
Area of RECTANGLES A = bh or A = lw Base x height length x width
Find the area and perimeter. Remember you can only combine “like” radicals! NOTE: It is a rectangle.
Give the expression for the area and perimeter. A = 2x(x – 3) A = 2x2 – 6x That is as far as you can go! P = 2(x – 3) + 2(2x) P = 2x – 6 + 4x P = 6x – 6 NOTE: It is a rectangle.
Find the area and perimeter. HINT: It’s a special right triangle! I love these guys! 300 5
SAT Problem • The area of the rectangle is 60 square units. Find the value of x. • ⅔ • 7 • 8 • 40 • 59 ½x 2x - 1 A = bh 60 = (2x – 1)(½x) 60 = x2 – ½x x = 8 0 = x2 – ½x – 60 0 = x2 – ½x – 60 This is UGLY. Try to Guess and Test.
How much will it cost to blacktop the driveway shown if blacktopping costs $11.00 per square meter? HINT: ADD A LINE!!!! A = 5(6) = 30 5 m HINT: You are finding area! 6 m A = 4(18) = 72 4 m TOTAL AREA = 72 + 30 = 102 m2 TOTAL COST = 102(11) = $1,122
Draw a picture • A path 2 m wide surrounds a rectangular garden 20 m long and 12 m wide. Find the area of the PATH. Total Area - Garden 384 – 240 = 144 m2 A = 24(16) = 384 m2 2 m 2 m A = 20(12) = 240 m2 12 m 16 m 2 m 20 m 2 m 24 m
PRACTICE • Page 426 • #2 – 12 EVENS • #23, 24
Area Video • Don’t you just love these videos!!!!