Question

T(8,15) is the midpoint of CD. The coordinates of d are (8,20) what are the coordinates of c

Answer 1

$coordinates\ of\ C(x,y)\\\\coordintaes\ of\ D(8,20)\\\\ T(8,15)=(\frac{8+x}{2}\ ;\ \frac{20+y}{2})\\\\8=\frac{8+x}{2}\ \ |*2\\\\16=8+x\\\\ 16-8=x\\\\x=8\\\\ 15=\frac{20+y}{2}\ \ |*2\\\\ 30=20+y\\\\y=30-20\\\\y=10\\\\ Q=(8,10)$