Lesson 10.1, For use with pages 521 nd the area of the triangle and rectangle. 1. 4 ft 3 ft 2. 15 m 15 m
Lesson 10.1, For use with pages 521-526
Find the area of the triangle and rectangle.
1.
4 ft
3 ft 2.
15 m
15 m
Lesson 10.1, For use with pages 521-526
Find the area of the triangle and rectangle.
ANSWER 6 ft2
ANSWER 225 m2
1.
4 ft
3 ft 2.
15 m
15 m
Bell Work
Talk with your partner about the homework that is due today. If it is a book assignment, please open your book
so you can look back at the question.
Discuss each of the following questions with each problem from homework:
How did you solve the problem?
Why did you solve it that way?
What did you get for your answer?
Circles10.2
How would you define a circle?
How do you know where the center of a circle is located?
The distance across the center of a circle is called the diameter. (Line segment AB below)The distance from the center to the edge of a circle is called the radius. (Segment CD)
TWO RADII = One Diameter
or the radius is ½ diameterD ÷ 2 = R
D
A
C
B
The distance around a circle is called the circumference.
C = d or C = 2 r
C = d or C = 2 r
Find the circumference: (round to nearest tenth)
r = 4 in C = 2 r
C = 3.14 x 2 x 4
C= 25.1 in
C = d or C = 2 r
Find the circumference:(round to nearest tenth)
d = 7 cm C = d
C = 3.14 x 7
C= 22.0 cm
Area of a circle is still the number of SQUARE UNITS inside the closed figure.
The area formula is A = r2
read Pi times the radius squared and it means Pi x radius x radius
A = r2
Find the area of the circle below
D = 10 in
A = r2
A = 3.14 x 52
A=78.5 in sq
A = r2
Find the area of the circle below
r = 3 cmA = r2
A = 3.14 x 32
A= 28.3 in sq
GUIDED PRACTICE for Examples 1 and 2
Find the area and circumference of the circle. Use 3.14 for л.
SOLUTION
A = лr 2
1. r = 7 ft
= 3.14 (7)2
= 153.9 ft2.
C = 2лr
= 2x 3.14 x 7
= 44.0 ft
GUIDED PRACTICE for Examples 1 and 2
Find the area and circumference of the circle. Use 3.14 for л.
SOLUTION
A = лr 2
2. d = 44 m
= 3.14 (22)2
= 1519.8 m2.
C = лd
= 3.14 x 44
= 138.2 m
Homework
Page 529 #4-7 Find both circumference and area for each
problem. ROUND TO THE NEAREST TENTH SHOW YOUR WORK!