Question

A formula for calculating A, the area of a trapezoid, is A= 1/2h (b1+b2), where is h is the height of trapezoid, and b1 and b2 are the lengths of the parallel sides. What is A when h= 4 centimetres, b1= 10 centimetres, and b2 = 5 centimetres?

Answer 1

The two parallel sides of a trapezoid are its bases. If we call the longer side b1 and the shorter side b2, then the base of the parallelogram is b1 + b2. Area of a trapezoid = 1 2 (base 1 + base 2)(height). A = 1 2 h(b1 + b2) The area of a trapezoid is half its height multiplied by the sum of its two bases.

Answer 2

Given: A = (½) * (b1 + b2) * h ;

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→Multiply EACH side of the equation by "2", to get rid of the fraction, "½";

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→ 2*A = 2 * (½) * (b1 + b2) * h ;

→ 2* A = 1 * (b1 + b2) * h ;

→ 2A = (b1 + b2) * h ;

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→ Now, divide EACH side of the equation by: "(b1 + b2)" ; to isolate "h" on one side of the equation;

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→ 2A / (b1 + b2) = [(b1 + b2) * h] / (b1 + b2) ;

→ 2A / (b1 + b2) = h ; ↔