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Circumference, Area,
Surface Area, and Volume
By Taylor Winter
Derive the Formula:
Area of a Triangle
Example Problems
1. A triangle has a base length of 5 cm and a height of 4 cm. What is the area of the triangle?
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Area of a triangle= (b x h)/2
b= 5 cm h= 4 cm
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(5 cm x 4 cm)/2
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20 cm2 / 2
The area is 10 cm^2.
Create a congruent triangle then using the moving and additive principle use the two congruent triangles to create a parallelogram.
The new parallelogram has an area two times the area of the original triangle.
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We know that the area of a parallelogram is base x height.
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The area of the triangle is half the area of the parallelogram.
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Area of a triangle is base x height divided by 2
2. A triangular window has the base of 7 ft and a height of 6 ft. What is the area of the window?
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Area of a triangle= (b x h)/2
b= 7 ft h= 6 ft
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(7 ft x 6 ft)/2
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42 ft2/2
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The area of the window is 21 ft^2.
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