PK 2019 Q8
8. Inside each unit square a certain part has been shaded. In which square is the total shaded area the largest?
Pink Kangaroo 2019, Question 8. © UK Mathematics Trust. Original paper on ukmt.org.uk
Answer: A
In each square, each triangle has height one unit. In each of the squares B, C, D, E, the sum of the bases of these triangles is one unit since they cover one side of the unit square, so the shaded area is half of each unit square. However, in square A, there is a rectangle which covers double the area of a triangle of height 1 on the same base. Thus A has the largest shaded area.
Solution © UK Mathematics Trust, from the PK 2019 solutions.