**Perimeter and Area of Composite Figures**

What is Area? What is Perimeter?

Area of a shape is the the amount of space inside the boundary of a flat (2-dimensional) object such as a triangle or circle. Usually the area of a shape is used to determine how much material would be needed to cover it.

Perimeter of a shape is the boundary around the shape, the distance around a two-dimensional shape. The distance around a circle is known as circumference.

How do you find the perimeter of a composite figure?

Composite Figures are figures (or shapes) that can be divided into more than one of the basic/simple figures (or shapes).

What is a Composite figure?

To find the area of composite figure, cut the shape into several simple figures (or shapes), which will make it easier to solve the composite shape itself. So what this means is to simply cut the shapes into basic shapes like a square, triangle, circle, etc. and then find their areas and then add them.

How do you find the area of a composite figure?

To know how to find the area and perimeter of a composite figure is really important because out in the real world everything isn't just a simple shape like a square, or a circle, or a triangle, for example your room, is it a perfect square? Most likely not, and if you want to paint your bedroom how would you know how much paint to buy?

Finding the area or perimeter of a composite figure can be useful if you're a builder or an architect, or for anyone,if you want to paint the house or put fencing you would need to first find out the area or perimeter of the figure, and most likely its going to be a composite figure.

When would finding area or perimeter of a composite shape be useful in real life?

The black borders around the shapes is the perimeter, and the space in the borders is the area.

perimeter

area

square

rectangle

triangle

square

rectangle

triangle

1) First Thing is write down the formulas and then substitute in the numbers....

Square+Triangle+Rectangle= Area of the composite figure

(b*h)+1/2(b*h)+(b*h)=area

(6*6)+1/2(6*9)+(10*20)=area

6

(6*6)+1/2(6*9)+(10*20)=area

36+1/2(54)+200=area

36+27+200=area

263=area *the area of this composite shape is 263cm

2) The next step is to simply solve the equation

Its not like this for all composite shapes but its similar to this.

1) cut into basic shapes

2) write an equation

3) substitute in the numbers

4) solve the equation and don't forget to add the units, which will always be units

2

2

To find the perimeter of a composite figure you just add the sides lengths, but sometimes this may require to find the circumference of a circle or the hypotenuse of a triangle, but you just use the simple formulas used to find the distance around the circle or the hypotenuse of a triangle, and then add them to find the distance around the whole composite figure

Some examples of Composite figures where you would need to find the circumference or the hypotenuse

1) Write the equation, the find out whether or not you need to find the hypotenuse or the circumference, if you do, then first find that and then go on to the next step, but if you don't then just go on to the next step, and solve the equation.

6

Write the equation

2(16)+20+5+2(6)+c = perimeter

Hypotenuse

6 + 9 = c

36 + 81 = c

117 = c√√

10.8 = c

2

2

2

2

2

2(16)+20+5+2(6)+c = perimeter

solve the equation

32+20+5+12+10.8=perimeter

79.8cm=perimeter