Lydia graphed ΔDEF at the coordinates D (−2, −1), E (−2, 2), and F (0, 0). She thinks ΔDEF is a right triangle. Is Lydia's assertion correct? Yes; the slopes of segment EF and segment DF are opposite reciprocals.
Yes; the slopes of segment EF and segment DF are the same.
No; the slopes of segment EF and segment DF are not opposite reciprocals.
No; the slopes of segment EF. and segment DF are not the same.

No; the slopes of segment EF and segment DF are not opposite reciprocals.

Step-by-step explanation:

The slope between two points O(e, f) and X (g,h) is given as:

The slopes of segment EF and segment DF are given below:

For triangle DEF to be a right triangle, DF and EF are supposed to be perpendicular to each other. Two line are said to be perpendicular if the product of their slope is -1, i.e the slope of one line is the negative reciprocal (opposite reciprocal) of the other line.

Since the slope of DF and EF are not opposite reciprocals,  ΔDEF is not a right triangle.

geometry: triangles

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call the larger triangle abc

then the smaller triangle cde is similar to abc (all angles are equal, aaa).  

ab is the side that is 36, and we wish to find de, the side corresponding to ab

area_cde = area_abc - area_cde --> area_abc / area_cde = 2

let x=length of de

ratio of areas = (ratio of sides)^2

+2+=+%2836%2fx%29%5e2+

+2+=+1296%2fx%5e2+

++x%5e2+=+1296%2f2+=+648+

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