Dillon W. answered • 06/12/16
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The area of a trapezoid is found by the equation
(B1+B2)/2*H=50
Where B1 and B2 are the different bases of the trapezoid. In this case, we don't know the values of the bases or the height, but we can still figure things out! The scale factor of the height increases by a factor of 4 (H becomes 4H). In order to make this change in the above equation, we have to multiply both sides of the equation by 4.
(B1+B2)/2*H*4=50*4
This is the equation that relates the new area of the figure when a scale factor of 4 is applied to the height of the original!
Kenneth S.
This all hinges on SEMANTICS. The problems not state that a uniform dilation has been applied, but only that the height is multiplied by 4.
Nowadays, with the strong emphasis on dilation transformations in the curriculum, it may be that this factor of 4 was a dilation scale factor--in which case the area of the transformed trapezoid is 16 times the original area.
However, there's no clear evidence that is the case here because the author of the problem student or teacher or Pearson publishing) took the unusual step of applying the scale factor only to the height.
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06/12/16
Mark M.
06/12/16