What this printable includes
Find the area of eight triangles from a supplied base and perpendicular height. Each item clearly labels the height as perpendicular, because a sloping side cannot automatically be used in the area formula. The page is calculation practice rather than a scale-drawing activity.
How to use the page
Multiply the base by the perpendicular height and divide by two. A triangle with base eight centimeters and height five centimeters has area twenty square centimeters. The units are squared because area measures a two-dimensional region, not the distance around the outside.
Review and adapt
Write the unit with each result and compare the answer with the area of a rectangle using the same base and height. The triangle should have half that rectangle’s area. All measurements are supplied, so no ruler is required. The answer page does not give perimeter because the remaining side lengths are not specified.
Answer key in text
- Base 8 cm; height 5 cm: 20 cm².
- Base 6 cm; height 7 cm: 21 cm².
- Base 10 cm; height 4 cm: 20 cm².
- Base 12 cm; height 9 cm: 54 cm².
- Base 14 cm; height 3 cm: 21 cm².
- Base 9 cm; height 8 cm: 36 cm².
- Base 16 cm; height 5 cm: 40 cm².
- Base 18 cm; height 7 cm: 63 cm².
Printable answer page
Download and print
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