17.8 Chapter summary

• Surface area is the total area of the exposed or outer surfaces of an object.
• Surface area is measured in square units.
• A net is a flat diagram that can be cut and folded to form a three-dimensional shape.
• Volume is the amount of the space that a three-dimensional object takes up.
• Volume is measured in cubic units.
• Capacity is the maximum amount that an object can hold.
• Capacity can be expressed in millilitres (\(\text{ml}\)) and litres (\(\text{l}\)).
• A cube is a solid with six identical square faces at right angles to each other.
• A cube unfolded into a net is made up of six identical squares.
• Volume of cube \(= \text{ length } \times \text{ breadth } \times \text{ height} = l^3\).
• A rectangular prism (also called a cuboid) is a solid with six rectangular faces at right angles to each other.
• A cuboid unfolded into a net has six rectangular faces.
• The volume of a cuboid is calculated by multiplying the area of the base by the height of the cuboid.
• Volume of cuboid \(= l \times b \times h\).
• A triangular prism has two identical triangular bases and three rectangular sides joined at right angles to the bases.
• To calculate the volume of a triangular prism, we must use the triangular face as the base of the prism.
• Volume of triangular prism \(= \text{area of base} \times h\).