Measure and calculate the perimeter of composite rectilinear shapes in centimetres and metres - Reasoning

In a mathematics reasoning task focusing on measurement, students are asked to calculate the perimeter of a composite rectilinear shape. The shape in question has a vertical line of symmetry, which is a crucial clue for solving the problem. The provided dimensions include two sides that measure 3.3 metres each and one side that measures 7.6 metres. To determine the value of the unknown side labelled 'c', students must apply their understanding of symmetry and perimeter.

The calculation begins by adding the known side lengths: 3.3 metres + 3.3 metres + 'c' equals the total given perimeter of 7.6 metres. This equation allows students to solve for 'c' by subtracting the sum of the known sides from the total perimeter. After performing the subtraction, it is found that 'c' equals 1 metre. This task not only tests the students' ability to measure and calculate perimeters but also reinforces their comprehension of symmetry in geometric shapes.