Answer:
(-1,-8)
Step-by-step explanation:
Multiply each value of midpoint by 2 and take away given points coordinates
Both of the other angles are 40° because a triangle has a total angle of 180° and an isosceles triangle means that at least two of the sides have to be the same length (two angles must be the same)
180 - 100= 80
80 ÷ 2 = 40
