Janelle S. answered 09/24/20
Penn State Grad for ME, Math & Test Prep Tutoring (10+ yrs experience)
X(−3, −6), Y(21, −6), and Z(21, 4)
Use the distance formula to find the length of each side:
distance = √[(x2 - x1)2 + (y2 - y1)2]
XY = √[(21 - (-3))2 + ((-6) - (-6))2] = √(242 + 02) = √576 = 24
YZ = √[(21 - 21)2 + ((4) - (-6))2] = √(02 + 102) = √100 = 10
XZ = √[(21 - (-3))2 + ((4) - (-6))2] = √(242 + 102) = √676 = 26
perimeter = XY + YZ + XZ = 24 + 10 + 26 = 60