When we look at composite shapes in geometry, it's important to know how perimeter and area work together.

Composite shapes are made by combining two or more simple shapes. These can be rectangles, triangles, and circles. Each of these shapes has its own ways to calculate perimeter and area.

Perimeter

The perimeter of a composite shape is the total distance around it. To find the perimeter, just add up the lengths of all the outside edges.

For example, if you have a shape made from two rectangles, you measure each side and add them up. Just remember not to count any sides that are inside the shape.

Example:

Let’s look at a composite shape that has a rectangle and a triangle:

• Rectangle: length = 4 units, width = 3 units
• Triangle: base = 3 units, height = 4 units

To find the perimeter:

• Rectangle perimeter = 2 x (4 + 3) = 14 units
• Triangle perimeter (if the other two sides are both 4 units) = 3 + 4 + 4 = 11 units

If these shapes are connected, we only count the outside edges.

Area

Area tells us how much space a shape takes up. To find the area of composite shapes, you calculate the area of each simple shape first, and then add them together.

Example:

For the same rectangle and triangle:

• Rectangle area = 4 x 3 = 12 square units
• Triangle area = 1/2 x 3 x 4 = 6 square units
• Total area = 12 + 6 = 18 square units

In short, the perimeter is about the distance around the shape, while area measures the space inside it. Knowing both of these for composite shapes helps improve your understanding of geometry!