Answer: 30 m ; (or, write as: "30 meters") .
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Explanation:
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Area of a trapezoid, "A" = (1/2) ( b₁ + b₂) h ;
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or, write as: A = ( b₁ + b₂) h / 2 ;
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in which: A = area;
b₁ = length of "base 1" (choose either one of the 2 (two bases);
b₂ = length of "base 2" (use the base that is remaining);
h = height of trapezoid;
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From the information given:
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A = 100 m² ;
h = 5 m
b₁ = 10 m
b₂ = x
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Find "x", which is: "b₂" ;
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A = ( b₁ + b₂) h / 2 ;
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Plug in our known values; and plug in "x" for "b₂" ; and solve for "x" ;
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100 m² = [(10m + x) (5m)] / 2 ; Solve for "x" ;
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(10m + x) (5m) = (2)* (100m²) ;
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(5m) (10m + x) = 200 m² ;
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Note: The distributive property of multiplication:
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a(b+c) = ab + ac ;
a(b−c) = ab − ac ;
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We have: (5m) (10m + x) = 200 m² ;
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So: (5m) (10m + x) = (5m*10m) + (5m * x) ;
= 50m² + (5m)x ;
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→ 50m² + (5m)x = 200m² ;
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Divide the ENTIRE equation by "5m" ;
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→ { 50m² + (5m)x } / 5m = (200m² / 5m) ;
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→ 10m + x = 40m ;
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Now, subtract "10m" from EACH side of the equation; to isolate "x" on one side of the equation; and to solve for "x" ;
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→ 10m + x − 10m = 40m − 10m ;
to get:
→ x = 30 m ; which is our answer.
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Answer: 30 m ; (or, write as: "30 meters") .
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