Area and Circumference of Circles Learning Pages

Your Turn!!

a) π + − ÷ × < > ≤ ≥ π

b)  π + − ÷ × < > ≤ ≥ π

Your Turn!!

Give your answers to 3 significant figures (s.f.) OR if you are going to revise rounding later then just write down the first 5 digits.

a) Calculate the circumference and area of a circle with radius 5 cm.

Circumference = π + − ÷ × < > ≤ ≥ π cm, Area = π + − ÷ × < > ≤ ≥ π cm²

b) The diameter of a circle is 10 cm; what is its radius? π + − ÷ × < > ≤ ≥ π cm

c) Calculate the perimeter and area of the quarter-circle above.

Hint: The perimeter is the distance around the shape. To work out the perimeter in c), start by calculating the circumference of a circle with radius 5 cm. To give you the curved length, divide this by 4. Then add on the extra 2 straight lengths.

Perimeter = π + − ÷ × < > ≤ ≥ π cm, Area = π + − ÷ × < > ≤ ≥ π cm²

Extra Your Turn!!

In Example 1 above, what is the exact area? π + − ÷ × < > ≤ ≥ π cm²

RAPID TEST

Give your answers to 3 significant figures (s.f.) OR if you are going to revise rounding later then just write down the first 5 digits.

1) For a circle with diameter 24 cm, as shown above, calculate:

a) the circumference π + − ÷ × < > ≤ ≥ π cm

b) the area π + − ÷ × < > ≤ ≥ π cm²

2) For the semicircle shown above, calculate:

a) the perimeter π + − ÷ × < > ≤ ≥ π cm

b) the area π + − ÷ × < > ≤ ≥ π cm²