Question

M is the midpoint line cd, where C is (-1,-1) and M is (3,5). Find the coordinates of D

Answer 1

The coordinates of point D are (7,11)

Explanation:

we know that

The formula to calculate the midpoint between two points is equal to

`M((x1+x2)/(2),(y1+y2)/(2))`

In this problem we have

`M=(3,5)\\C(x1,y1)=(-1,-1)\\D(x2,y2)=?`

substitute the given values

`(3,5)=((-1+x2)/(2),(-1+y2)/(2))`

Solve for x2

`(-1+x2)/(2)=3` --->
`-1+x2=6` --->
`x2=6+1=7`

Solve for y2

`(-1+y2)/(2)=5` --->
`-1+y2=10` --->
`y2=10+1=11`

therefore

The coordinates of point D are (7,11)