Max Maths, Year 5, Learn together, Perimeter of shapes (2)

In a Year 5 mathematics lesson, students are tasked with calculating the perimeter of an L-shaped room with various given lengths and widths. To find the perimeter, one must first identify the length of each side of the room. The diagram provided labels the sides from A to F, with A being 25 metres, B 100 metres, D 30 metres, and E 20 metres. To determine the unknown lengths, C and F, simple addition and subtraction are used. Side C is the sum of sides A and E, which equates to 45 metres (25m + 20m), while side F is the difference between sides B and D, resulting in 70 metres (100m - 30m).

With the length of each side now known, students can proceed to calculate the total perimeter of the room. The perimeter is the sum of all side lengths: A, B, C, D, E, and F. By adding these together, 25 metres plus 100 metres plus 45 metres plus 30 metres plus 20 metres plus 70 metres, the students find that the perimeter of the L-shaped room is 290 metres. This exercise demonstrates how to approach finding the perimeter when not all side lengths are immediately known and reinforces the concept that the perimeter is the total distance around the edge of a shape.