3rd Grade Perimeter Quiz: 10 Questions with Explanations

A 13 inchesB 18 inchesC 26 inchesD 40 inches

Add all four sides: 8 + 5 + 8 + 5 = 26. Adding only two sides gives 13, and 40 is the area.

A The distance around a shapeB The space inside a shapeC The number of cornersD The longest side

Perimeter is the total length of the boundary. The space inside is the area.

A 15 inchesB 17 inchesC 20 inchesD 26 inches

Add all three sides: 6 + 9 + 11 = 26. Leaving out a side gives 15, 17, or 20.

A 4 centimetersB 7 centimetersC 14 centimetersD 21 centimeters

A square has 4 equal sides, and 28 divided by 4 is 7. Dividing by 2 gives 14, which is a width plus a length.

A 14 feetB 7 feetC 17 feetD 24 feet

Two lengths make 20, and 34 – 20 = 14 is left for two widths, so one width is 7. Subtracting only one length gives 24.

A 17 metersB 19 metersC 30 metersD 22 meters

Add all six sides: 6 + 2 + 3 + 3 + 3 + 5 = 22. Skipping a side gives 19 or 17, and 30 is 6 times 5.

A 3 by 6 and 2 by 8B 2 by 7 and 4 by 5C 4 by 5 and 2 by 10D 1 by 9 and 3 by 3

Both 2 by 7 and 4 by 5 have a perimeter of 18, and their areas are 14 and 20. In the other pairs, the perimeters are different.

A 480 yardsB 240 yardsC 330 yardsD 13,500 yards

Perimeter is 2 times (150 + 90), which is 480. Adding two sides gives 240, and 13,500 is the area.

A 1 by 16B 2 by 8C 4 by 4D 8 by 2

The perimeters are 16 for 4 by 4, 34 for 1 by 16, and 20 for both 2 by 8 and 8 by 2. The shape closest to a square has the smallest.

A 45 feetB 14 feetC 36 feetD 81 feet

A regular pentagon has 5 equal sides, and 5 times 9 is 45. Using 4 sides gives 36.