Question

Drag the tiles to the correct boxes to complete the pairs. Not all tiles will be used.

Match each circumference to the corresponding radius or diameter of the circle. (All circumferences are approximate.)

Answer 1

26.376 units

23.236 units

34.54 units

59.66 units

Explanation:

The formula for the circumference of a circle is ...

C = 2πr = πd

C = 2(3.14)r = 6.28r or C = 3.14d

where r is the radius and d is the diameter.

Put the given radius or diameter into the relevant formula and compute the product. The results are all in "units".

r = 4.2 ⇒ C = 6.28×4.2 = 26.376

d = 7.4 ⇒ C = 3.14×7.4 = 23.236

d = 11 ⇒ C = 3.14×11 = 34.54

r = 9.5 ⇒ C = 6.28×9.5 = 59.66

Explanation:

Answer 2

• 26.376 units
• 23.236 units
• 34.54 units
• 59.66 units

Explanation:

The formula for the circumference of a circle is ...

C = 2πr = πd

C = 2(3.14)r = 6.28r or C = 3.14d

where r is the radius and d is the diameter.

Put the given radius or diameter into the relevant formula and compute the product. The results are all in "units".

r = 4.2 ⇒ C = 6.28×4.2 = 26.376

d = 7.4 ⇒ C = 3.14×7.4 = 23.236

d = 11 ⇒ C = 3.14×11 = 34.54

r = 9.5 ⇒ C = 6.28×9.5 = 59.66