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Question 1 of 4
Find the area of the Circle
Round your answer to 1 decimal place
Use π=3.141592654
Incorrect
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Given Lengths
diameter=18
First, find the radius of the circle. Note that the radius is half of the diameter.
radius |
= |
diameter2 |
|
|
= |
182 |
|
radius |
= |
9 |
Finally, solve for the area using the formula: A=πr2
Area |
= |
π×radius2 |
Area of a Circle Formula |
|
= |
3.141592654×92 |
Plug in the known values |
|
= |
3.141592654×81 |
Evaluate |
|
= |
254.46900 |
|
= |
254.5 mm2 |
Rounded to 1 decimal place |
The given measurements are in millimetres, so the area is measured as square millimetres
Area=254.5 mm2
The answer will depend on which π you use.
In this solution we used: π=3.141592654.
π=3.141592654 |
254.5 mm2 |
π=3.14 |
254.3 mm2 |
π=227 |
254.6 mm2 |
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Question 2 of 4
Find the area of the Circle
Round your answer to 1 decimal place
Use π=3.14
Incorrect
Given Lengths
diameter=24
First, find the radius of the circle. Note that the radius is half of the diameter
radius |
= |
diameter2 |
|
|
= |
242 |
|
radius |
= |
12 |
Finally, solve for the area using the formula: A=πr2
Area |
= |
π×radius2 |
Area of a Circle Formula |
|
= |
3.14×122 |
Plug in the known values |
|
= |
3.14×144 |
Evaluate |
|
= |
452.16 |
|
= |
452.2 m2 |
Rounded to 1 decimal place |
The given measurements are in metres, so the area is measured as square metres
Area=452.2 m2
The answer will depend on which π you use.
In this solution we used: π=3.14.
π=3.14 |
452.2 m2 |
π=3.141592654 |
452.4 m2 |
π=227 |
452.6 m2 |
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Question 3 of 4
Find the area of the Circle
Round your answer to 1 decimal place
Use π=3.14
Incorrect
First, find the radius of the circle
Note that the radius is half of the diameter
radius |
= |
diameter2 |
|
|
= |
42 |
|
radius |
= |
2 |
Finally, solve for the area using the formula: A=πr2
Area |
= |
π×radius2 |
Area of a Circle Formula |
|
= |
3.14×22 |
Plug in the known values |
|
= |
3.14×4 |
Evaluate |
|
= |
12.56 |
|
= |
12.6 cm2 |
Rounded to 1 decimal place |
The given measurements are in centimetres, so the area is measured as square centimetres
Area=12.6 cm2
The answer will depend on which π you use.
In this solution we used: π=3.14.
π=3.14 |
12.6 cm2 |
π=3.141592654 |
12.6 cm2 |
π=227 |
12.6 cm2 |
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Question 4 of 4
Find the area of the yellow-shaded region.
Round your answer to 2 decimal places
Use π=3.141592654
Incorrect
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Given Lengths
radius (Larger Semicircle)=7
diameter (Smaller Semicircle)=7
First, solve for the area of the Larger Semicircle
AreaLarger Semicircle |
= |
12×π×radius2 |
|
= |
12×3.141592654×72 |
Area |
= |
76.96902 m2 |
We can see on the image that the diameter of the Smaller Semicircle is 7
We will use that to solve for the radius of the Smaller Semicircle, which is half of its diameter
radiusSmaller Semicircle |
= |
diameter2 |
|
= |
72 |
|
= |
3.5 m |
Next, find the area of the Smaller Semicircle
AreaSmaller Semicircle |
= |
12×π×radius2 |
|
= |
12×3.141592654×3.52 |
Area |
= |
19.24225 m2 |
Finally, add the area of the Larger Semicircle and the area of the Smaller Semicircle
Final Area |
= |
76.96902+19.24225 |
|
= |
96.21127 |
|
= |
96.21 m2 |
Rounded to 2 decimal places |
The given measurements are in metres, so the area is measured as square metres
Area=96.21 m2
The answer will depend on which π you use.
In this solution we used: π=3.141592654.
π=3.141592654 |
96.21 m2 |
π=3.14 |
96.16 m2 |
π=227 |
96.25 m2 |