Question

A triangle is graphed in the coordinate plane. The vertices of the triangle have coordinates (-4,1)(1,1), and (1,-11). What is the perimeter of the triangle?

A. 30
B.17
C. 25
D. 18

Answer 1

To answer the question above, determine the distance between the points which are the vertices of the triangle.

1. Between (-4,1) and (1,1) ;     d1 = sqrt ((1-1)² + (1--4)²) = 5
2. Between (-4,1) and (1,-11) ;  d2 = sqrt ((-11-1)² +(1--4)²) = 13
3. Between (1,1) and (1,-11) ;    d3 = sqrt ((-11-1)² + (1-1)²) = 12

The perimeter is the sum of the three distances. Thus, the perimeter of the triangle is 30. The answer is letter A.