Canada Grade 8 Math Calculating with area, volume, and capacity

What is the area of a rectangle with a length of 8 metres and a width of 5 metres?

• 13 square metres

• 40 square metres

• 30 square metres

• 20 square metres

Answer explanation

The area of a rectangle is calculated by multiplying the length by the width. Here, 8 metres (length) x 5 metres (width) = 40 square metres. Therefore, the correct answer is 40 square metres.

A cube has a side length of 4 cm. What is its volume?

• 16 cubic centimetres

• 64 cubic centimetres

• 32 cubic centimetres

• 48 cubic centimetres

Answer explanation

The volume of a cube is calculated using the formula V = side³. For a cube with a side length of 4 cm, V = 4 cm × 4 cm × 4 cm = 64 cubic centimetres. Therefore, the correct answer is 64 cubic centimetres.

• 282.6 cubic centimetres

• 94.2 cubic centimetres

• 188.4 cubic centimetres

• 150.8 cubic centimetres

Answer explanation

The volume of a cylinder is calculated using the formula V = πr²h. Substituting the values, V = 3.14 * (3 cm)² * 10 cm = 3.14 * 9 * 10 = 282.6 cubic centimetres. Thus, the correct answer is 282.6 cubic centimetres.

What is the area of a triangle with a base of 10 metres and a height of 6 metres?

• 30 square metres

• 60 square metres

• 20 square metres

• 40 square metres

Answer explanation

The area of a triangle is calculated using the formula: Area = 0.5 × base × height. Here, Area = 0.5 × 10 m × 6 m = 30 square metres. Therefore, the correct answer is 30 square metres.

A rectangular prism has dimensions of 5 cm by 3 cm by 2 cm. What is its volume?

• 30 cubic centimetres

• 15 cubic centimetres

• 10 cubic centimetres

• 20 cubic centimetres

Answer explanation

To find the volume of a rectangular prism, multiply its dimensions: 5 cm × 3 cm × 2 cm = 30 cubic centimetres. Therefore, the correct answer is 30 cubic centimetres.

What is the capacity in litres of a container that holds 2500 cubic centimetres of water?

• 2.5 litres

• 25 litres

• 0.25 litres

• 250 litres

Answer explanation

To convert cubic centimetres to litres, divide by 1000. Thus, 2500 cm³ ÷ 1000 = 2.5 litres. Therefore, the correct answer is 2.5 litres.

• 153.86 square centimetres

• 38.48 square centimetres

• 49 square centimetres

• 21.98 square centimetres

Answer explanation

The area of a circle is calculated using the formula A = πr². Substituting r = 7 cm and π ≈ 3.14, we get A = 3.14 × (7)² = 3.14 × 49 = 153.86 square centimetres. Thus, the correct answer is 153.86 square centimetres.

What is the surface area of a cube with a side length of 5 cm?

• 150 square centimetres

• 125 square centimetres

• 100 square centimetres

• 75 square centimetres

Answer explanation

The surface area of a cube is calculated using the formula 6a², where a is the side length. For a side length of 5 cm, the surface area is 6 * (5 cm)² = 6 * 25 cm² = 150 cm². Thus, the correct answer is 150 square centimetres.

A swimming pool is 25 metres long, 10 metres wide, and 2 metres deep. What is its volume?

• 500 cubic metres

• 250 cubic metres

• 100 cubic metres

• 50 cubic metres

Answer explanation

To find the volume of the pool, multiply its length, width, and depth: 25m x 10m x 2m = 500 cubic metres. Therefore, the correct answer is 500 cubic metres.

What is the perimeter of a rectangle with a length of 12 metres and a width of 7 metres?

• 38 metres

• 24 metres

• 19 metres

• 42 metres

Answer explanation

The perimeter of a rectangle is calculated using the formula P = 2(length + width). Here, P = 2(12 + 7) = 2(19) = 38 metres. However, the correct perimeter is 42 metres, indicating a possible error in the question or choices.