1. The diagram shows a shape made from ten squares of side-length $1 \mathrm{~cm}$, joined edge to edge.
What is the length of its perimeter, in centimetres?
A 14
B 18
C 30
D 32
E 40
Solution
B

Counting the edges of the squares around the shape gives a perimeter of $18 \mathrm{~cm}$.