Grade 6, Measurement and geometry
Area of triangles
Find the area of triangles as half of base times height, or find a missing base or height.
Three levels
One skill, rising difficulty
Each sheet carries one level. The three are the same skill at rising difficulty, each named for what it practises.
- Level 1: Base and height to 10
- Find the area of each triangle.
- Level 2: Base or height above 10
- Find the area of each triangle. Some answers end in .5.
- Level 3: Find the missing base or height
- Use the area to find the missing base or height of each triangle.
Worked example
How the sheet explains it
The helper printed at the top of each sheet: one solved example and the steps a student follows, before the first question. Every number sentence in it is proven by the same checker as the answer key.
Level 1: Base and height to 10
- A triangle is half of a parallelogram with the same base and height.
- Area of a triangle = base × height, then halve it.
- Area = 10 × 7 ÷ 2 = 70 ÷ 2 = 35 cm².
Level 2: Base or height above 10
- Area of a triangle = base × height, then halve it.
- Base × height = 15 × 9 = 135.
- Halve it: 135 ÷ 2 = 67.5, so the area is 67.5 cm².
Level 3: Find the missing base or height
Area = 27 cm² Base = 9 cm Height = 6 cm
- Undo the halving first: double the area. 2 × 27 = 54.
- Base × height = 54, so divide by the measure you know: 54 ÷ 9 = 6.
- Check: 9 × 6 ÷ 2 = 27 cm². The height is 6 cm.
Goes with
Reference sheets
One-page helpers a student keeps beside this sheet:
- Perimeter and area
- Formulas to remember
Every reference, facts and support sheet is listed in the worksheet catalogue.
In the BC curriculum
Content standards
The British Columbia content standard this skill is written for, by the codes used across this site:
- bc.math.6.c.12
The wording of each standard is on the Province's mathematics curriculum page.
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