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We suggest you take the math of least resistance.

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In the graph below, AB equals CD. What is the value of z?

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Here are the potential answers...

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First of all, we don’t see any triangles in this diagram… but we’re about to.

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Let’s draw ourselves an imaginary right triangle… or an actual one, if you’ve

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got a marker and don’t mind drawing on your computer monitor…

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…with CD as the hypotenuse. We can tell by subtracting the x and y values

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from the coordinates that one leg will have a length of 3…

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…and the other will have a length of 4.

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We should be able to recognize that this is a 3, 4, 5 triangle…

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Since we are told that both lines, or in our case, both hypotenuses, are of equal length…

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…we know that the side lengths of our second right triangle must be 3 and 4 as well.

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If we look at the difference between the x values, we can see that -3.5 is three units

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left of -0.5. Which tells us that the OTHER leg must be

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FOUR units in length. We’re given the y value of 1.5…

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…so for the leg of our triangle to have a length of 4, the other y value must be -2.5.

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And we’ve got our answer – option C.

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