# Volume and Surface Area

# The 3rd Dimension

Measuring shapes gets three dimensional on the GED. From the surface area of a sphere, to the volume of a pyramid, you're got to be prepared for more complex geometry formulas.

## LEARN IT

Imagine a 3-dimensional shape like the one above, a cube, or a host of others: balls, boxes, cylinders. There are two ways to measure 3-dimensional shapes like these:

1)** Surface Area:** the surface area is the number of square units it takes to cover a 3-D shape- imagine wrapping paper. It's a 2-D measurement wrapped around a 3-D shape.

2)** Volume:** Volume, on the other handing, isn't a covering, it fills a 3-D shape. Like the water in a water bottle or the sand in a sandbox. Because volume completely fills a 3-D space, it's also 3-dimensional so it's measured in cubic units.

As usual, with GED Geometry these formulas show up on the GED **formula sheet** so all you have to do is choose the appropriate formula, substitute in the known values, then rely on your algebra skills to solve for the unknown variable.

### Watch the Virtual GED Class video below for a complete explanation and tons of worked example problems.

## PRACTICE IT

Volume and surface area in GED style word problems.

## WORKED EXAMPLES

Visualization 1

Beginner 1

Beginner 2

Beginner 3

Beginner 4

Experienced 1

Experienced 2

Experienced 3

Experienced 4

Advanced 1

Advanced 2

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Advanced