# How do you find the missing coordinate if the 1st coordinate is (12, -8) and the midpoint is (3, 18)?

##### 1 Answer

Apr 13, 2018

#### Explanation:

#"the coordinates of the midpoint are the average of the"#

#"coordinates of the endpoints"#

#"here one endpoint is "(12,-8)#

#"let the endpoint to be found "=(x,y)#

#rArr1/2(12+x)=3larrcolor(blue)"x-coordinate of midpoint"#

#"multiply both sides by 2"#

#rArr12+x=6rArrx=6-12=-6#

#rArr1/2(-8+y)=18larrcolor(blue)"y-coordinate of midpoint"#

#"multiply both sides by 2"#

#rArr-8+y=36rArry=36+8=44#

#rArr"coordinates of missing endpoint "=(-6,44)#