Answer
x=11
y=19
The distance formula shows the MC=MD.
Work Step by Step
a) use the midpoint formula
$M(\frac{x_1+x_2}{2},\frac{y_1+y_2}{2})$
substitute
$M(\frac{5+17}{2},\frac{9+29}{2})$
$M(\frac{22}{2},\frac{38}{2})$
$M(11,19)$
b) use the distance formula to show the distance is the same from the midpoint to each endpoint.
$d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}$
$d=\sqrt{(5-11)^2+(9-19)^2}$
$d=\sqrt{(-6)^2+(-10)^2}$
$d=\sqrt{36+100}$
$d=\sqrt{136}$
$d=11.7\checkmark$
$d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}$
$d=\sqrt{(17-11)^2+(29-19)^2}$
$d=\sqrt{(6)^2+(10)^2}$
$d=\sqrt{36+100}$
$d=\sqrt{136}$
$d=11.7\checkmark$
