Work through the levels in order. Type your answer and press Check — open the worked solution if you get stuck. Answers like -6, 3/4 or 0.25 are typed exactly as shown. A ⭐ Bonus Challenge at the end is extra credit — skip it if the rest was hard work.
Level 1 · Warm-up
1 A shape has sides 6, 4, 3, 2, 3, 6 cm. Perimeter in cm?
Show worked solution
6 + 4 + 3 + 2 + 3 + 6 = 24 cm.
2 A square has side 9 cm. Perimeter in cm?
Show worked solution
4 × 9 = 36 cm.
3 Should a perimeter be written in cm or cm2?
Show worked solution
cm. Squared units are for area only.
Level 2 · Core
4 An L-shape has a top edge of 12 cm; the bottom is two edges, 7 cm and one unlabelled. Find the unlabelled edge, in cm.
Show worked solution
12 − 7 = 5 cm.
5 A rectangle is 1.5 m by 60 cm. Perimeter in metres?
Show worked solution
60 cm = 0.6 m → 2(1.5) + 2(0.6) = 4.2 m.
6 A semicircle has diameter 14 cm and its flat edge is on the outside. Total perimeter, to 1 dp, in cm? (π ≈ 3.142)
Show worked solution
½ × 3.142 × 14 = 22.0, plus the 14 cm flat edge → 36.0 cm.
Level 3 · Challenge
7 A rectangle has sides x and 9 cm and perimeter 44 cm. Find x, in cm.
Show worked solution
2x + 18 = 44 → 2x = 26 → x = 13 cm.
8 A garden is a 20 m by 12 m rectangle. Fencing goes round it but a 3 m gate needs no fence. How many metres of fence?
Show worked solution
Perimeter = 2(20) + 2(12) = 64 m; minus the 3 m gate → 61 m.
9 A shape is a 10 cm by 6 cm rectangle with a semicircle of diameter 6 cm on one short end (the join is internal). Perimeter to 1 dp, in cm? (π ≈ 3.142)
Show worked solution
10 + 10 + 6 = 26, plus ½ × 3.142 × 6 = 9.4 → 35.4 cm. The join is internal, so it is not counted.