Question

I only need number 10 plz help!!!!!!!

Answer 1

9514 1404 393

Answer:

• DE ≈ 9.49, EF ≈ 8.06, FD ≈ 14.87
• obtuse scalene triangle

Step-by-step explanation:

For finding side lengths, it is convenient to work with the differences of the coordinates.

  DE = E(-1, -3) -D(8, -6) = (-9, 3)

  EF = F(-2, 5) -E(-1, -3) = (-1, 8)

  FD = D(8, -6) -F(-2, 5) = (10, -11)

Then the lengths are ...

  DE = √((-9)² +3²) = √90 = 3√10 ≈ 9.49

  EF = √((-1)² +8²) = √65 ≈ 8.06

  FD = √(10² +(-11)²) = √221 ≈ 14.87

The lengths are all different and the largest angle is obviously more than 90°, so the triangle is an obtuse scalene triangle.