12.4 The Distance Formula
Objectives: Use the distance formula to find the distancebetween 2 points in a coordinate plane. Determine whether atriangle is a right triangle. Apply the midpoint formula.
Standard Addressed: 2.1.11.A Use operations.
•
Ex. 1
Ex. 1 C. (4, 5) and (-5, 7)
•9.22
Ex. 2
Ex. 2b. Given vertices P(-1, -2), Q (5, 2),and R (-3, 1), determine whether trianglePQR is a right triangle.
•Right Triangle
Ex. 3
•3 + 11 , 8 + 2
2 2
(7, 5)
Ex. 4a. The center M (3, 4). If oneendpoint of a diameter is A (-4, 6),what is the other endpoint, B (x2, y2)?
•3 = x + (-4)
2
6 = -4 + x
X = 10
4 = y + 6
2
8 = y + 6
y = 2
(10, 2)
Ex. 4b. If the center of a circle is M(-1, -2) andone endpoint of a diameter is A(4, 3), what is theother endpoint, B (x2, y2)?
•-1 = x + 4
2
-2 = 4 + x
X = -6
-2 = y + 3
2
-4 = 3 + y
y = -7
(-6, -7)
