Circumference of Circles

Question 1 of 7

Find the circumference of the circle

Round your answer to

2

$2$ decimal places

Use

π = 3.14

$pi=3.14$

$Circumference =$ $\text(Circumference )=$ (37.68, 37.70, 37.71) $c m$ $cm$

Using	Answer
$π = 3.14$ $pi=3.14$	$37.68 c m$ $37.68 cm$
$π = 3.141592654$ $pi=3.141592654$	$37.70 c m$ $37.70 cm$
$π = \frac{22}{7}$ $pi=(22)/(7)$	$37.71 c m$ $37.71 cm$

Question 2 of 7

Find the circumference of the circle

Round your answer to

1

$1$ decimal place

Use

π = \frac{22}{7} or π = 3.14

$pi=22/7 \text(or) pi=3.14$

$Circumference =$ $\text(Circumference )=$ (50.3, 50.2) $c m$ $cm$

Using	Answer
$π = \frac{22}{7}$ $pi=(22)/(7)$	$50.3 c m$ $50.3 cm$
$π = 3.14$ $pi=3.14$	$50.2 c m$ $50.2 cm$
$π = 3.141592654$ $pi=3.141592654$	$50.3 c m$ $50.3 cm$

Question 3 of 7

Find the circumference of the Circle

Round your answer to

1

$1$ decimal place

Use

π = 3.14

$pi=3.14$

$Circumference =$ $\text(Circumference )=$ (47.1) $c m$ $cm$

Using	Answer
$π = 3.14$ $pi=3.14$	$47.1 c m$ $47.1 cm$
$π = 3.141592654$ $pi=3.141592654$	$47.1 c m$ $47.1 cm$
$π = \frac{22}{7}$ $pi=(22)/(7)$	$47.1 c m$ $47.1 cm$

Question 4 of 7

Find the circumference of the circle

Round your answer to

1

$1$ decimal place

Use

π = \frac{22}{7} or π = 3.14

$pi=22/7 \text(or) pi=3.14$

$Circumference =$ $\text(Circumference )=$ (163.4, 163.3) $m m$ $mm$

Using	Answer
$pi=(22)/(7)$	$163.4 mm$
$pi=3.14$	$163.3 mm$
$pi=3.141592654$	$163.4 mm$

Question 5 of 7

Find the perimeter of the Semi-circle

Round your answer to

$1$ decimal place

Use

$pi=3.141592654$

$\text(Perimeter )=$ (102.8, 102.9) $mm$

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Mute

Perimeter of a Semicircle

$\text(Perimeter)=\frac{1}{2}times pi times$ $\text(diameter)$

Given Lengths

$\text(diameter)=40$

Solve for the perimeter using the formula

Use

$pi=3.141592654$ See

$pi$ explained

$\text(Perimeter)$ _{$\text(Semicircle)$}	$=$	$\frac{1}{2}times pi times$ $\text(diameter)$	Circumference of a Semi-Circle Formula

	$=$	$\frac{1}{2}times 3.141592654 times$ $40$	Plug in the known values

	$=$	$62.8318 mm$

Note that

$62.8318 mm$ is just the curve of the Semicircle

Add the length of the Line under the curve which is equal to the diameter.

$\text{Final Perimeter}$	$=$	$62.8318$ $+40$
	$=$	$102.8318 mm$
	$=$	$102.8 mm$	Rounded to $1$ decimal place

$\text(Perimeter)=102.8 mm$

The answer will depend on which

$pi$ you use.

In this solution we used:

$pi=3.141592654$ .

Using	Answer
$pi=3.141592654$	$102.8 mm$
$pi=3.14$	$102.8 mm$
$pi=(22)/(7)$	$102.9 mm$

Question 6 of 7

Find the perimeter of the shape

Round your answer to

$1$ decimal place

Use

$pi=3.141592654$

$\text(Perimeter )=$ (41.1) $cm$

Using	Answer
$pi=3.141592654$	$41.1 cm$
$pi=3.14$	$41.1 cm$
$pi=(22)/(7)$	$41.1 cm$

Question 7 of 7

Find the perimeter of the shape

Note that the radius of the larger semi-circle is

$12cm$ .

Round your answer to

$1$ decimal place

Use

$pi=3.141592654$

$\text(Perimeter )=$ (68.5, 68.6) $cm$

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Mute

Perimeter of a Semicircle

$\text(Perimeter)=\frac{1}{2}times pi times$ $\text(diameter)$

Or

$\text(Perimeter)=pi times$ $\text(radius)$

Given Lengths

$\text(diameter)$ (Smaller Semicircle)

$=12$

$\text(radius)$ (Larger Semicircle)

$=12$

Solve for the perimeter of the Larger Semicircle

Use

$pi=3.141592654$ See

$pi$ explained

$\text(Perimeter)$ _{$\text(Larger Semicircle)$}	$=$	$pi times$ $\text(radius)$	Perimeter of a Semicircle Formula
	$=$	$3.141592654 xx$ $12$	Plug in the known values
	$=$	$37.69911 cm$

Solve for the perimeter of the Smaller Semicircle

Use

$pi=3.141592654$ See

$pi$ explained

$\text(Perimeter)$ _{$\text(Smaller Semicircle)$}	$=$	$\frac{1}{2}times pi times$ $\text(diameter)$	Perimeter of a Semicircle Formula

	$=$	$\frac{1}{2}times 3.141592654 times$ $12$	Plug in the known values

	$=$	$18.84955 cm$

Now add the two perimeters

$\text(Perimeter)$	$=$	$37.69911$ $+$ $18.84955$
	$=$	$56.54866 cm$
	$=$	$56.5 cm$	Rounded to $1$ decimal place

Finally, add the value of the straight line, which is

$12$ , to get the
total perimeter

$\text{Total Perimeter}$	$=$	$56.5$ $+$ $12$
	$=$	$68.5 cm$

$\text(Perimeter)=68.5 cm$

The answer will depend on which

$pi$ you use.

In this solution we used:

$pi=3.141592654$ .

Using	Answer
$pi=3.141592654$	$68.5 cm$
$pi=3.14$	$68.5 cm$
$pi=(22)/(7)$	$68.6 cm$

$Circumference$ $\text(Circumference)$	$=$ $=$	$2 \times π \times$ $2 xx pi xx$ $radius$ $\text(radius)$	Circumference Formula
	$=$ $=$	$2 \times 3.14 \times$ $2 times 3.14 times$ $6$ $6$	Plug in the known values
	$=$ $=$	$6.28 \times 6$ $6.28 times 6$	Evaluate
	$=$ $=$	$37.68 c m$ $37.68 cm$

$Circumference$ $\text(Circumference)$	$=$ $=$	$2 \times π \times$ $2 xx pi xx$ $radius$ $\text(radius)$	Circumference Formula
	$=$ $=$	$2 \times \frac{22}{7} \times$ $2 times 22/7 times$ $8$ $8$	Plug in the known values
	$=$ $=$	$\frac{44}{7} \times 8$ $44/7 times 8$	Evaluate
	$=$ $=$	$\frac{352}{7}$ $352/7$	$352 \div 7$ $352 divide 7$
	$=$ $=$	$50.28571$ $50.28571$
	$=$ $=$	$50.3 c m$ $50.3 cm$	Rounded off to $1$ $1$ decimal place

$Circumference$ $\text(Circumference)$	$=$ $=$	$π \times$ $pi xx$ $diameter$ $\text(diameter)$	Circumference Formula
	$=$ $=$	$3.14 \times$ $3.14 times$ $15$ $15$	Plug in the known values
	$=$ $=$	$47.1 c m$ $47.1 cm$

$Radius$ $\text(Radius)$	$=$ $=$	$\frac{1}{2} \times$ $1/2 xx$ $diameter$ $\text(diameter)$
	$=$ $=$	$\frac{1}{2} \times$ $1/2 xx$ $52$ $52$
$Radius$ $\text(Radius)$	$=$ $=$	$26$ $26$

$Circumference$ $\text(Circumference)$	$=$ $=$	$2 \times π \times$ $2 xx pi xx$ $radius$ $\text(radius)$	Circumference Formula
	$=$ $=$	$2 \times \frac{22}{7} \times$ $2 xx 22/7 xx$ $26$ $26$	Plug in the known values
	$=$ $=$	$\frac{44}{7} \times$ $44/7 xx$ $26$ $26$	Evaluate
	$=$ $=$	$\frac{1144}{7}$ $1144/7$	$1144 \div 7$ $1144 divide 7$
	$=$ $=$	$163.42857‬$
	$=$	$163.4 mm$	Rounded to $1$ decimal place

Circumference of Circles

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Quiz summary

Information

1. Question

Hint

Great Work!

Circumference Formula

Given Lengths

2. Question

Hint

Correct!

Circumference Formula

Given Lengths

3. Question

Hint

Keep Going!

Circumference Formula (using diameter)

Given Lengths

4. Question

Hint

Fantastic!

Circumference Formula

Given Lengths

5. Question

Hint

Excellent!

Perimeter of a Semicircle

Given Lengths

6. Question

Hint

Nice Job!

Perimeter of a Semicircle

Given Lengths

7. Question

Hint

Exceptional!

Perimeter of a Semicircle

Given Lengths

Quizzes

$\text(Perimeter)$ _{$\text(Square)$}	$=$	$9 + 9 + 9$	Add the $3$ sides
	$=$	$27 cm$

$\text(Total Perimeter)$	$=$	$14.13716$ $+$ $27$
	$=$	$41.13716$
	$=$	$41.1 cm$	Rounded to $1$ decimal place