## anonymous one year ago D(5, 7), E(4, 3), and F(8, 2) form the vertices of a triangle. What is m DEF?

1. anonymous

area?

2. anonymous

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3. mathmate

To find m$$\angle$$DEF calculate the slopes of DE and EF and examine the values. To find slopes, use the following formula: slope =$$\Large \frac{y_2-y_1}{x_2-x_1}$$ If the product of two slopes equal -1, then the two lines are perpendicular to each other.