To find the area of a triangle, we use the formula:
Area = (base × height) ÷ 2
We’ll go through each triangle one by one. All measurements are in inches (“in”).
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Triangle 1:
- Base = 30 in
- Height = 18 in
→ Area = (30 × 18) 2 = 540 2 =
270 in²
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Triangle 2:
- Base = 24 in
- Height = 12 in
→ Area = (24 × 12) ÷ 2 = 288 ÷ 2 =
144 in²
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Triangle 3:
- Base = 12 in
- Height = 6 in
→ Area = (12 × 6) ÷ 2 = 72 ÷ 2 =
36 in²
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Triangle 4:
This is an obtuse triangle — but the height is drawn outside, perpendicular to the extended base.
- Base = 15 in
- Height = 9 in
→ Area = (15 × 9) ÷ 2 = 135 ÷ 2 =
67.5 in²
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Triangle 5:
Right triangle — legs are base and height.
- Base = 10 in
- Height = 24 in
→ Area = (10 × 24) 2 = 240 2 =
120 in²
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Triangle 6:
Isosceles triangle with height from apex to base.
- Base = 16 in
- Height = 10 in
→ Area = (16 × 10) ÷ 2 = 160 ÷ 2 =
80 in²
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Triangle 7:
Right triangle again.
- Base = 18 in
- Height = 24 in
→ Area = (18 × 24) ÷ 2 = 432 ÷ 2 =
216 in²
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Triangle 8:
Obtuse triangle — height is drawn outside.
- Base = 12 in
- Height = 5 in
→ Area = (12 × 5) ÷ 2 = 60 ÷ 2 =
30 in²
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Triangle 9:
Right triangle — note: the right angle is at the bottom left, so legs are base and height.
- Base = 15 in
- Height = 8 in
→ Area = (15 × 8) ÷ 2 = 120 ÷ 2 =
60 in²
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Final Answer:
1) 270 in²
2) 144 in²
3) 36 in²
4) 67.5 in²
5) 120 in²
6) 80 in²
7) 216 in²
8) 30 in²
9) 60 in²
Parent Tip: Review the logic above to help your child master the concept of triangle problems worksheet.
