Grade 7 · Math · Unit 12 of 16
Area & Constructions
Triangles, parallelograms and bisectors
What your child practises
Area of triangles and parallelograms using base and height, and the vocabulary of perpendicular and parallel lines and bisectors.
Nunavut Curriculum approved guide: Alberta Mathematics K–9 (2007), Shape and Space · area of triangles and parallelograms, and perpendicular, parallel and bisector constructions
Sample questions
A taste of this unit. In the app, questions change every time and get easier or harder to match your child.
Question 1
A parallelogram has a base of 8 cm, a height of 9 cm and a slanted side of 13 cm. What is its area, in square centimetres?
- 72
- 71
- 76
72
Hint: Use the height (the straight-up distance), not the slanted side: base × height = 8 × 9.
Question 2
A triangle has a base of 7 cm and a height of 6 cm. What is its area, in square centimetres?
- 21
- 17
- 15
21
Hint: Area of a triangle = base × height ÷ 2 = 7 × 6 ÷ 2.
Question 3
A triangle and a rectangle have the same base and the same height. How do their areas compare?
- The triangle's area is a quarter of the rectangle's
- They are equal
- The triangle's area is half the rectangle's
- The triangle's area is double the rectangle's
The triangle's area is half the rectangle's
Hint: Two matching triangles fit together to make the rectangle (or a parallelogram), so each is half.
Question 4
An angle bisector cuts a 40° angle into two equal angles. How large is each one, in degrees?
- 20
- 19
- 16
20
Hint: Bisect means to cut into two equal parts. Divide by 2.
Question 5
A parallelogram has a base of 14 cm, a height of 4 cm and a slanted side of 7 cm. What is its area, in square centimetres?
- 56
- 58
- 55
56
Hint: Use the height (the straight-up distance), not the slanted side: base × height = 14 × 4.
Question 6
A triangle has an area of 36 cm² and a base of 8 cm. What is its height, in centimetres?
- 11
- 9
- 8
9
Hint: Area × 2 ÷ base = height.