Michael J. answered • 09/19/16
Tutor
5
(5)
Effective High School STEM Tutor & CUNY Math Peer Leader
Use the distance formula:
d2 = (x1 - x2)2 + (y1 - y2)2
where:
d = 20
Point 1 = (5, y)
Point 2 = (-2, 7)
202 = (5 - (-2))2 + (y - 7)2
400 = 72 + (y - 7)2
400 = 49 + (y - 7)2
351 = (y - 7)2
Square-root both sides of the equation.
±√(351) = y - 7
Add 7 to both sides of the equation.
7 ± √(351) = y
y1 = 7 - √(351) and y1 = 7 + √(351)
