Measuring the area of an irregularly shaped, flat object, e.g. your hand.
1. You will need graph paper and a pencil. 2. Using a pencil, trace the outline of your hand onto squared paper.
3. Count the number of 1 cm2 find the area of your hand.
squares that are covered to 4. Count any square that is more than half covered.
Calculating surface area We can also calculate the surface area of 3D objects. For example a cube has six square sides so the surface area of a cube can be calculated using the formula, Area = 6x2
, where x is the length of the side
of the cube. More complex formulas are needed to calculate the surface area of other shapes.
x x2 x2 x x x2
Fig. 12 Calculating the surface area of a cube. Each of the six sides has a surface area of x2.
Research this Can you find out how you would calculate the surface area of the following types of object?
x2 x2 x2
Fig. 11 Measuring the area of the shape of your hand.
Cube
Rectangular prism 27.7 Volume
Volume is a measure of how much space something takes up. The units of volume are m3
, cm3 and mm3 .
Measuring volume 1. Regularly shaped boxes: Multiply the length by the width by the height.
2. Liquids: Pour the liquid into a graduated cylinder and read the volume.
l w
Fig. 13 The volume of a regularly shaped box is l x w x h.
