Question

What is the perimeter of ABC with vertices A(-2,9), B(7,-3), and C(-2,-3) and in the coordinate plain?

A. 21 units
B. 15 units
C. 34 units
D. 36 units

Answer 1

36units

Step-by-step explanation: A - C = ( -2, 9) - (- 2 -3)

= ( 0, 12)

AC = 12

B - C = (7 - 3) - ( - 2 -3)

= (9, 0)

BC = 9

ABC is a right -angled triangle with AC as the hypotenuse

AC = sqrt( 9^2 + 12^2)

= sqrt(81 + 144)

= srqt(225)

= 15

Perimeter = 12 + 9 + 15

= 36 units

So the answer is 36 units

Answer 2

Explanation:

A - C = ( -2, 9) - (- 2 -3)

= ( 0, 12)

AC = 12

B - C = (7 - 3) - ( - 2 -3)

= (9, 0)

BC = 9

ABC is a right -angled triangle with AC as the hypotenuse

AC = sqrt( 9^2 + 12^2)

= sqrt(81 + 144)

= srqt(225)

= 15

Perimeter = 12 + 9 + 15

= 36 units

So the answer is 36 units