Grade 7 Test Questions: Calculating Area of a Circle (Radius/Diameter)

📚 Quick Study Guide

• 📐 The radius of a circle is the distance from the center to any point on the circle.
• 📏 The diameter of a circle is the distance across the circle through the center. It is twice the length of the radius.
• ➗ Diameter = 2 * Radius; Radius = Diameter / 2
• 🧮 The formula for the area of a circle is: $A = \pi r^2$, where $A$ is the area, $\pi$ (pi) is approximately 3.14159, and $r$ is the radius.
• 🔑 If you are given the diameter ($d$), you can find the radius by dividing the diameter by 2: $r = \frac{d}{2}$. Then, use the area formula.

📝 Practice Quiz

1. What is the area of a circle with a radius of 5 cm?
   1. A) 15.71 cm²
   2. B) 31.42 cm²
   3. C) 78.54 cm²
   4. D) 157.08 cm²
2. The diameter of a circle is 10 meters. What is its area?
   1. A) 31.42 m²
   2. B) 78.54 m²
   3. C) 157.08 m²
   4. D) 314.16 m²
3. A circle has a radius of 3.5 inches. Find its area.
   1. A) 19.24 in²
   2. B) 38.48 in²
   3. C) 31.42 in²
   4. D) 153.94 in²
4. If the diameter of a circle is 14 cm, what is the area of the circle?
   1. A) 43.98 cm²
   2. B) 615.75 cm²
   3. C) 153.94 cm²
   4. D) 87.96 cm²
5. A circular garden has a radius of 8 meters. What is the area of the garden?
   1. A) 50.27 m²
   2. B) 100.53 m²
   3. C) 201.06 m²
   4. D) 64 m²
6. The area of a circle is needed for a project. The diameter is 6 inches. What is the area?
   1. A) 9.42 in²
   2. B) 18.85 in²
   3. C) 28.27 in²
   4. D) 113.10 in²
7. Calculate the area of a circle if its radius is 12 mm.
   1. A) 37.70 mm²
   2. B) 75.40 mm²
   3. C) 144 mm²
   4. D) 452.39 mm²