Circles (circumference, area) Knowledge-Based Download PDF

Questions

1. 1.

   The circumferences of two concentric circles are $28\pi\text{ cm}$ and $20\pi\text{ cm}$. What is the area of the region bounded between the two circles, in square centimeters?

   • A) $16\pi$
   • B) $96\pi$
   • C) $144\pi$
   • D) $192\pi$
2. 2.

   Two circles have circumferences in the ratio $2 : 5$. If the area of the smaller circle is $12\pi\text{ cm}^2$, what is the area of the larger circle?

   • A) $30\pi\text{ cm}^2$
   • B) $48\pi\text{ cm}^2$
   • C) $75\pi\text{ cm}^2$
   • D) $150\pi\text{ cm}^2$
3. 3.

   If the area of a circle is $100\pi\text{ cm}^2$, what is the circumference of the circle in centimeters?

   • A) $10\pi\text{ cm}$
   • B) $40\pi\text{ cm}$
   • C) $25\pi\text{ cm}$
   • D) $20\pi\text{ cm}$
4. 4.

   The circumference of a circle is increased from $10\pi\text{ cm}$ to $16\pi\text{ cm}$. By how many square centimeters does the area of the circle increase?

   • A) $9\pi\text{ cm}^2$
   • B) $21\pi\text{ cm}^2$
   • C) $39\pi\text{ cm}^2$
   • D) $54\pi\text{ cm}^2$
5. 5.

   A circle has a circumference of $24\pi\text{ cm}$. What is the area of the circle?

   • A) $24\pi\text{ cm}^2$
   • B) $48\pi\text{ cm}^2$
   • C) $144\pi\text{ cm}^2$
   • D) $576\pi\text{ cm}^2$