Rectangle sides and angles

Mathematics · Geometry · ages 9-10

Name ______________________ Date ____________

In a rectangle, the two sides across from each other are always the same length.
Circle one: True False
Which of these is true about every rectangle?
- All four angles are right angles
- All four sides are the same length
- It has exactly three corners
- Its diagonals are sides
A rectangle that is 7 units long and 3 units wide has a perimeter of 20 units.
Circle one: True False
How many degrees is each angle inside a rectangle?
- 180°
- 90°
- 45°
A rectangle has an area of 24 square units. One side is 6 units long. How long is the other side?
Answer: ______________
A rectangle has a perimeter of 20 units. One side is 6 units long. How long is the other side?
Answer: ______________
A rectangle has one side 5 m and a perimeter of 18 m. What is the other side?
- 9 m
- 4 m
- 13 m
Which rectangle has a perimeter of exactly 20 units?
- 5 units by 5 units
- 6 units by 5 units
- 4 units by 5 units
- 8 units by 4 units
Ava has 12 square tiles and uses all of them each time. If turning a rectangle around does not count as a new rectangle, how many different rectangles can she make?
- 2
- 3
- 4
- 6
Zack says: 'My rectangle has one side 9 cm and a perimeter of 30 cm, so the other side is 30 - 9 = 21 cm.' What mistake did Zack make?
- He should have added instead of subtracted
- He used the wrong side length
- He forgot to divide the perimeter by 2 before subtracting

Answer key

For grown-ups. Fold this page away before handing over the rest.

True · Opposite sides of a rectangle always match in length, so if you know one side, you already know its opposite.
All four angles are right angles · Every rectangle has four corners, and each corner is a right angle, which means 90 degrees. Only opposite sides have to be equal.
True · The four sides are 7, 3, 7, and 3. Adding them gives 20, so the statement is true.
90° · A rectangle's corners are right angles, and every right angle measures 90°.
4 · Area is length times width, so the two sides multiply to 24. Since 6 times 4 is 24, the missing side is 4 units.
4 · The perimeter is the total distance around. Two sides of 6 use up 12 units, leaving 8 units for the other two equal sides, so each is 4 units.
4 m · Half of 18 is 9, and since one side is 5, the other side is 9 - 5 = 4 m. Stopping at 9 skips the last step.
5 units by 5 units · Perimeter is the sum of all four sides. A 5 by 5 rectangle has sides 5, 5, 5, and 5, which add to 20.
3 · The rectangles are 1 by 12, 2 by 6, and 3 by 4. That is 3 different rectangles, because 4 by 3 is just 3 by 4 turned around.
He forgot to divide the perimeter by 2 before subtracting · Zack skipped a step. He needed to divide 30 by 2 to get 15 first, then subtract 9 to get 6 cm.