Examples with solutions for Area of a Circle: How many times does the shape fit inside of another shape?

Exercise #1

Given two circles - one has a radius of 4 cm and the other has a radius of 10 cm.

How many times can the area of the small circle fit into the large circle?

410

Step-by-Step Solution

To solve this problem, we need to find how many times the area of the small circle fits into the area of the large circle. We'll do this by calculating both areas and finding their ratio.

Step 1: Identify the given information
We have two circles:

  • Small circle with radius r1=4 r_1 = 4 cm
  • Large circle with radius r2=10 r_2 = 10 cm

Step 2: Calculate the area of the small circle
Using the formula for the area of a circle A=πr2 A = \pi r^2 , we get:
A1=π42=π16=16π A_1 = \pi \cdot 4^2 = \pi \cdot 16 = 16\pi square cm

Step 3: Calculate the area of the large circle
Similarly, for the large circle:
A2=π102=π100=100π A_2 = \pi \cdot 10^2 = \pi \cdot 100 = 100\pi square cm

Step 4: Find how many times the small area fits into the large area
We divide the large area by the small area:
A2A1=100π16π=10016 \frac{A_2}{A_1} = \frac{100\pi}{16\pi} = \frac{100}{16}

Step 5: Simplify the fraction
10016=254 \frac{100}{16} = \frac{25}{4}

Step 6: Convert to a mixed number
254=614 \frac{25}{4} = 6\frac{1}{4}

This makes sense because when we scale a circle's radius by a factor of 104=2.5 \frac{10}{4} = 2.5 , its area scales by the square of that factor: (2.5)2=6.25=614 (2.5)^2 = 6.25 = 6\frac{1}{4} .

Therefore, the area of the small circle fits into the large circle 614 6\frac{1}{4} times.

Answer

614 6\frac{1}{4}

Exercise #2

A rectangle and a circle are shown below.

How many times does the area of the circle fit into the area of the rectangle without a remainder?

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Video Solution

Answer

Once

Exercise #3

How many times does the smaller circle fit into the larger circle?

RRR4R4R4R

Video Solution

Answer

16 time.