Triangle and Circle Areas

Name:

Date:

📚 Part 1: Multiple Choice

1. If the diameter of a circle is 10 cm, the radius is:

5 cm

10 cm

20 cm

2. What is the area of a triangle with base 8 cm and height 6 cm?

24 cm²

48 cm²

14 cm²

3. Using π ≈ 3.14, what is the area of a circle with radius 7 cm? (Choose the closest)

154 cm²

439 cm²

44 cm²

4. Check all correct statements about doubling the radius of a circle:

The area doubles

The area becomes four times larger

The circumference becomes four times larger

✏️ Part 2: Short Answers and Calculations

5. Draw and label: On the circle below, draw a radius from the centre to the circumference and a diameter through the centre. Label the centre O and the point on the circumference A.

6. Calculate the area of a triangle with base 12 m and height 5 m. Show working and write the unit.

7. A semicircle has diameter 10 cm. Using π ≈ 3.14, find its area. Give your answer to one decimal place.

8. A composite shape: a triangle (base 6 cm, height 4 cm) is attached to a semicircle with diameter 6 cm along the base. Calculate the total area. Use π ≈ 3.14 and give units.

9. Precision and units: A circle has diameter 2.5 m. Calculate its area in m² using π ≈ 3.14 and give your answer to two decimal places. Include units.

10. In one sentence, explain why doubling a linear measurement (like radius) changes area by a factor of the square of that scaling.