When wrapping birthday or Christmas presents, the larger the gift, the more wrapping paper is needed. Here you can see the measurements of two birthday presents that Victor has bought for his wife.
a) What is the surface area of the cuboid box of shortbread?
b) What is the surface area of the triangular prism of chocolate?
Victor has a piece of wrapping paper that measures 30cm x 40cm.
c) Is Victor’s wrapping paper large enough to cover both of the gifts?
This video is a very practical example of surface area, and works well to consolidate learning in class. Students need to be able to recall areas of rectangles and triangles, and also recognise markings on triangles to denote the type of triangle that it is. It normally takes students around 8 minutes to solve this, although it sometimes works to split the class into two groups, each group handling one of the shapes. A similar video exists in the ‘circles’ section which includes the area of a cylinder.
Teachers could extend the learning by considering:
- Create an additional gift which combines different units – mm, cm or metres and ask students to work out the surface area of that gift.
- Provide the area of an alternate piece of wrapping paper in metres squared, and ask students if that piece of paper would wrap all the gifts. This leads nicely into conversion of squared or cubed units.