Grade 8 Surface Area and Volume

Interactive step-by-step solver for understanding the space occupied by and the total area of 3D shapes.

Volume Area
Learning Mode
Practice Mode
Related Concepts

Step-by-Step Learning

Learn about the surface area and volume of common 3D shapes.

Example 1: Surface Area vs. Volume

Explain the difference between surface area and volume.

Surface Area: The total area of all the faces (surfaces) of a three-dimensional object. Think of it as the amount of wrapping paper needed to cover the object. The unit is in square units (e.g., cm2).
Volume: The amount of space a three-dimensional object occupies. Think of it as the amount of liquid a container can hold. The unit is in cubic units (e.g., cm3).
Key Difference: Surface area is a measure of the exterior, while volume is a measure of the interior space.
Surface Area vs Volume Interior Space (Volume) Exterior Area (Surface Area)

Example 2: Surface Area of a Cuboid

Explain how to find the surface area of a cuboid and provide the formula.

Step 1: A **cuboid** is a 3D shape with 6 rectangular faces. Opposite faces are identical.
Step 2: To find the total surface area, you calculate the area of each of the six faces and add them together.
Step 3: Let the length be 'l', width be 'w', and height be 'h'. The pairs of identical faces have areas:
  • Top and Bottom: l × w
  • Front and Back: l × h
  • Left and Right Sides: w × h
Step 4: The formula for the total surface area of a cuboid is:
Surface Area = 2(lw + lh + wh)
Step 5: The unit of surface area is in square units (e.g., cm2).
Surface Area of Cuboid l h w SA = 2(lw + lh + wh)

Example 3: Volume of a Cuboid

Explain how to find the volume of a cuboid and provide the formula.

Step 1: The **volume** of a cuboid is the amount of space it occupies.
Step 2: To find the volume of a cuboid, you multiply its length, width, and height.
Step 3: Let the length be 'l', width be 'w', and height be 'h'. The formula for the volume of a cuboid is:
Volume = length × width × height or Volume = lwh
Step 4: The unit of volume is always in cubic units (e.g., cm3, m3).
Volume of Cuboid l h w Volume = l × w × h

Example 4: Surface Area and Volume of a Cube

Explain how to find the surface area and volume of a cube and provide the formulas.

Step 1: A **cube** is a special type of cuboid where all six faces are congruent squares. All edges have the same length.
Step 2: Let the length of an edge of the cube be 's'.
Step 3: **Surface Area of a Cube:** Since there are 6 identical square faces, and the area of one square face is side × side (s × s or s2), the total surface area is 6 times the area of one face.
Surface Area = 6 × side × side or Surface Area = 6s2
Step 4: **Volume of a Cube:** Using the cuboid volume formula (l × w × h) and knowing that for a cube l=w=h=s, the volume is side × side × side.
Volume = side × side × side or Volume = s3
Step 5: Remember to use square units for surface area and cubic units for volume.
Cube Formulas s SA = 6s2 Volume = s3

Practice Mode

Enter a simple surface area or volume problem to solve.

Note: This basic solver can calculate the surface area or volume of cuboids and cubes. Specify the shape and its dimensions (e.g., "surface area of cuboid l=10 w=5 h=4", "volume of cube side=6", "SA of cube s=7", "Volume of cuboid 8x3x5").