Step: 1

The circumference of a circle = π × diameter.

[Formula.]

Step: 2

= 3.14 × 24

[Substitute π = 3.14 and diameter = 24 cm.]

Step: 3

= 75.36 cm.

[Simplify.]

Step: 4

The circumference of the basketball hoop is 75.36 cm.

Correct Answer is : 75.36 cm

Step: 1

The diameter of the circle is 21 inches.

[Given.]

Step: 2

The circumference of a circle = π × diameter.

[Formula.]

Step: 3

The circumference of the circle = 3.14 × 21.

[Substitute π = 3.14 and diameter = 21 inches.]

Step: 4

= 65.94 inches

Step: 5

The circumference of the circle is 65.94 inches.

Correct Answer is : 65.94 inches

Step: 1

The radius (r ) of the circle is 48 cm.

[Given.]

Step: 2

The circumference of the circle = 2 × π × r

[Formula.]

Step: 3

= 2 × 3.14 × 48

[Substitute π = 3.14 and r = 48 cm.]

Step: 4

= 301.44 cm

[Simplify.]

Step: 5

The circumference of the circle is 301.44 cm.

Correct Answer is : 301.44 cm

Step: 1

Evaluate 2πr for r = 5

Step: 2

2πr = 2π(5)

[Substitute r for 5.]

Step: 3

= 10π

[Multiply.]

Step: 4

The circumference of the circle is 10π.

Correct Answer is : 10π

Step: 1

Circumference of the wheel = π d

Step: 2

π × 100

[Substitute d = 100.]

Step: 3

100π cm.

Step: 4

The distance covered by the wheel in one revolution = Circumference of the circle

Step: 5

Number of revolutions of the wheel while travelling 700 cm.

700/100π = 7/π

Correct Answer is : 7/π

Step: 1

Let r _{1} and r _{2} be the radii of outer and inner circles.

Step: 2

Circumference of the outer circle, 2π r _{1} = 160 m.

Step: 3

[Divide each side by 2π .]

Step: 4

Circumference of the inner circle, 2π r _{2} = 132 m.

Step: 5

[Divide each side by 2π .]

Step: 6

The difference between their radii = 80/π - 66/π

= 14/π m.

Correct Answer is : 14/π m

Step: 1

Let d be the diameter of the circle.

Step: 2

The circumference of the circle = π d .

Step: 3

The diameter of a circle is increased by 80%.

Step: 4

The new diameter of the circle = (1 + 0.8) × d = 1.8d

Step: 5

The new circumference of the circle = π × 1.8d = 1.8 π d

Step: 6

The circumference of the circle is increased by 80%.

Correct Answer is : 80%

Step: 1

Let r be the radius of the circle.

Step: 2

The radius of a circle is decreased by 30%.

Step: 3

The new radius of the circle = (1 - 0.3) × r = 0.7r

Step: 4

Circumference of the circle = 2π r

Step: 5

The new circumference of the circle = 2 × π × 0.7r

Step: 6

= 0.7 × 2π r

Step: 7

= (1 - 0.3) × 2π r

Step: 8

So, the circumference of the circle is decreased by 30%.

Correct Answer is : 30%

Step: 1

The circumference of a circle = π × diameter

Step: 2

= 3.14 × 25

[Substitute π = 3.14 and diameter = 25 cm.]

Step: 3

= 78.50 cm

Step: 4

The circumference of the basketball hoop is 78.50 cm.

Correct Answer is : 78.50 cm

Step: 1

Circumference of a circle with diameter d = πd

[Formula.]

Step: 2

Circumference of the circle = 2.7cm.

Step: 3

From Steps(1) and (2), πd = 2.7

Step: 4

3 × d = 2.7

[Substitute π = 3.]

Step: 5

3d = 2.7

Step: 6

[Divide each side by 3.]

Step: 7

d = 0.9

[Simplify.]

Step: 8

The diameter of the circle is 0.9cm.

Correct Answer is : 0.9 cm

Step: 1

The shape of the garden is circle.

Step: 2

Therefore, the distance covered by John = the circumference of the circle.

Correct Answer is : circumference

- Complementary, Supplementary, Vertical and adjacent Angles-Gr 7-Solved Examples
- Finding Missing Angles in Polygons-Gr 7-Solved Examples
- Scale Drawings-Gr 7-Solved Examples
- Application Problems involving Scale Drawings-Gr 7-Solved Examples
- Solving Problems on Area of a Circles-Gr 7-Solved Examples
- Perimeter and Area of Composite Figures-Gr 7-Solved Examples

- Circumference