Circles
Circumference
Area
Scale Factor
Area of Composite Figures
100
Define radius
The radius goes from the center of the circle to one edge of a circle.
100
What is the circumference when the diameter is 10?
31.4
100
What happens to my units when I use the area formula?
They become squared
100
What is the same has multiplying by 1/6?
Dividing by 6
100
Determine the area of the entire figure
(6.5)(13) = 84.5
3.14(3.25 * 3.25) = 33.17
84.5 + 33.17 = 117.67
117.67 square feet
200
Define diameter
The diameter goes from one edge to the other edge of the circle through the middle
200
What is the circumference when the radius is 6?
37.68
200
What is the area if my radius is 5?
78.5
200
What is the same as dividing by 5?
Multiplying by 1/5
200
The radius for the little circle is 3 meters, the radius for the large circle is 8 meters. Calculate the area of the walkway around the fountain.
3.14(8 * 8) = 200.96
3.14(3 * 3) = 28.26
200.96 - 28.26 = 172.7
172.7 square meters
300
What is the circumference of a circle?
3.14*d
2*3.14*r
300
What is the circumference if the radius is 16?
100.48
300
What is the area if the diameter is 6?
28.26
300
My original circle has a diameter of 10. If I multiply my circle by a scale factor of 5:1 what is my new diameter?
50
300
Are these triangles congruent?
Yes, both have a right angle
400
What is the area of a circle?
3.14*r2
400
What is the radius if the circumference is 200.36?
31.9
400
What is the area if my diameter is 18?
254.34
400
My original circle has a radius of 4. If I multiply by a scale factor of 1:2 what is the radius of my new circle?
2
400
Are these triangles congruent?
Yes, both have a 29 degree angle and share angle T
500
What is the radius if the diameter is 40
20
500
What is the diameter if the circumference is 143.17?
45.59
500
What is my area if my radius is 14?
615.44
500
If my model car is 1:12 the size of my actual car, how much bigger is my actual car?
12 times as big
500
Are these triangles congruent?
Yes, both have a right angle and share angle Q