Central Distance
Age
11 to 14
Challenge level
Weekly Problem 1 - 2006
The diagram shows two circles enclosed in a rectangle. What is the distance between the centres of the circles?
Problem
Image
The diagram shows two circles enclosed in a rectangle measuring 9cm by 5 cm.
What is the distance between the centres of the circles?
If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.
Student Solutions
The diameter of the circles is 5cm, so the radius of the circles is 2.5cm.
Each centre is 2.5cm from the nearest side of the rectangle.
So the distance between them is (9 - (2 x 2.5))cm = 4cm