Transcript PowerPoint
SECTION 11.1
AREAS of RECTANGLES and SQUARES
WARM UP 1) Find the area and perimeter of a square that is 5 inches long.
A = 5 · 5 = 25 2) The area of a square is 64 cm 2 . What is the perimeter?
3) The perimeter of a square is 28 inches. What is the area?
PERIMETER •
TO FIND PERIMETERS
•
Add all the side lengths together!
Area of SQUARES
• Area of a square = sides 2 =
s 2
A
2 2 4 9 2 3
Area of RECTANGLES
•
A = bh or A = lw
•
Base x height length x width
A
4 2 3
A
8 3
Find the area and perimeter.
6 2 4 5
P A
A A
24 10 5 2
w
2
P
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 = 2x 2 – 6x That is as far as you can go!
x - 3 P = 2(x – 3) + 2(2x) P = 2x – 6 + 4x P = 6x – 6 2x NOTE: It is a rectangle.
5 3 30 0
Find the area and perimeter.
10
60
HINT: It’s a special right triangle! I love these guys!
A
A
25 3
P
P
5
SAT Problem • The area of the rectangle is 60 square units. Find the value of
x
.
a) ⅔ b) 7 c) 8
x = 8
d) 40 e) 59
½x 2x - 1 A = bh 60 = (2x – 1)(
½x)
60 = x 2 – ½x 0 = x 2 – ½x – 60 0 = x 2 – ½x – 60
Real Life Applications
• How much will it cost to blacktop the driveway shown if blacktopping costs $11.00 per square meter? HINT: ADD A LINE!!!!
HINT: You are finding area!
12 m
A = 5(6) = 30 6 m 5 m
9m 4 m
TOTAL AREA = 72 + 30 = 102 m 2 A = 4(18) = 72 TOTAL COST = 4 m
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
.
A = 24(16) = 384 m 2
2 m 2 m
A = 20(12) = 240 m 2 20 m 24 m 12 m
2 m
16 m
2 m
PRACTICE
• Page 426 • #2 – 12
EVENS
•
#23, 24
Area Video • Don’t you just love these videos !!!!