What type of triangle is formed by joining the points D(7,3) E(8,1) and F(4,-1)?

Answer:A right triangle  Step-by-step explanation:If you plot the triangle as in the figure below, it looks like a right triangle. It should satisfy Pythagoras' Theorem:    AB²    +     AC²   =    BC² Each side of the triangle is the hypotenuse of a smaller right triangle.(2² + 4²) + (2² + 1²) = (4² + 3²) (4 + 16)  +   (4 + 1)   =  16 + 9    20     +       5      =      25             25             =      25 The theorem is satisfied. ∆ABC is a right triangle.