Question

The formula for the area A of a trapezoid is A=1/2(b1+b2)h, where b1 and b2 represents the lengths of the bases and h represents the height. Which equation can be used to find the height of a trapezoid?
A. h=2A-b1-b2
B. h=2A/b1+b2
C. h=A(b1+b2)/2
D. h=A-2/b1-b2

Answer 1

The answer:  [B]:  h = 2A / (b1 + b2) .
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Explanation:

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 ; ↔ h = 2A / (b1 + b2) ; which corresponds to:
                                            "Answer choice: [B]" .
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