THE TEST MAKERS’ FAVORITE SOLID
The test makers’ favorite solid is the rectangular solid. That’s the official
geometric term for a box that has 6 rectangular faces and 12 edges that meet
at right angles at 8 vertices.
SURFACE AREA OF A RECTANGULAR SOLID
If the length is ℓ, the width is w, and the height is h, the formula is
Surface Area = 2ℓw + 2wh + 2ℓhThe surface area of a rectangular solid is simply the sum of the areas of the
faces. That’s what the formula “Surface Area = 2ℓw + 2wh + 2ℓh” says. if the
length is ℓ, the width is w, and the height is h, then two rectangular faces have
area ℓw, two have area wh, and two have area ℓh. The total surface area is the
sum of those three pairs of areas.
Instead of the surface area, you may be asked to find the distance between
opposite vertices of a rectangular solid. Look at Example 2.