Question

PLEASE HELP!!

Quadrilateral ABCD is similar to Quadrilateral EFGH. Diagonal AC has length 7 and diagonal EG has length 13. What is the scale factor that describes a dilation from BC to FG? Give the exact scale factor and state whether the dilation is an expansion or a contraction.

If side AB has length 17/26 what is the length of side EF? Give the exact, un-rounded value.

If the area of ABCD is 147 square inches, what is the area of EFGH? Give the exact answer.

Answer 1

13/7, 221/182 and expansion, 507 inches

Explanation:

If the two quadrilaterals are similar, you can take the diagonal length as a similar side to find the scale factor. In this case, the scale factor would be 13/7. For simplicity, we can keep this a factor for now. Because the quadrilaterals are similar, the scale factor is the same for all sides, 13/7. Because you are going from ABCD to EFGH and the scale factor is 13/7 (otherwise the other way around would be 7/13) and so the scale factor is greater than 1, you are expanding aka expansion. So, to find EF from side AB and you have the length 17/26, just multiply that by 13/7 to get 221/182 as the length.

To find the area of EFGH, you square the scale factor 13/7 and equal it to the area of EFGH A is over the area of the ABCD (you ratio them and set them equal) so 169/49 = A/147 and solve for A which is then 49A = 169 x 147 which is then 507 inches.