Answer: 10.5 units
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Step-by-step explanation:
Both AB and XY are the first two letters of ABC and XYZ respectively. So we have one fraction of AB/XY = 2/7.
AC and XZ are the first and last letters of ABC and XYZ respectively. We can form another fraction AC/XZ. I'm dividing in the same order of small over large to keep things consistent. As you can probably guess, the order of the letters ABC and XYZ are important so we see how the angles match up and how the proportional sides match up.
Because the triangles are similar, the two fractions formed earlier are equal to one another.
The equation we need to solve is AB/XY = AC/XZ
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AB/XY = AC/XZ
2/7 = 3/N ... plug in given values
2N = 7*3 .... cross multiply
2N = 21
N = 21/2 .... divide both sides by 2
N = 10.5
ZX is 10.5 units long.