A large square of side-length 10 cm contains a smaller square of side-length 4 cm, as shown in the diagram. The corresponding sides of the two squares are parallel. What percentage of the area of the large square is shaded?
A 25% B 30% C 40% D 42% E 45%
D
The length of the big square is 10 cm and of the smaller is 4 cm. The total height of the shaded regions is 6. Hence the total area of the two trapezoids combined is 10+4 2 × 6 = 42 cm2 . Since the total area is 100 cm2 this is 42 %.
Preparing for the Junior Maths Challenge?
Join a free weekly live lesson where I solve real JMC-style problems, explain key methods, and share what to focus on in your weekly practice.
You can join live or watch the replay - everyone is welcome.
📅 Every Tuesday
⏰ 18:30–19:30 (UK time)
💻 Live session (link sent by email)

This course guides you through the fundamentals of Python programming using an interactive Python library known as Turtle.

This course encompasses a range of Geometry topics such as coordinate and spatial geometry, introductory trigonometry, angles, parallel lines, congruent and similar triangles, polygons, circles, the Pythagorean Theorem, and more. Emphasis will be placed on reinforcing Algebra skills and enhancing critical thinking through problem-solving in both mathematical and real-world contexts.

Ask about our courses and offerings, and we will help you choose what works best for you.