Answer:
28 cm
Step-by-step explanation:
Triangle ABC is obtained by joining the mid points of the sides of triangle XYZ.
So, perimeter of triangle ABC will be equal to half of the perimeter of triangle XYZ.

Answer:
Check explanation.
Step-by-step explanation:
slope-intercept form: y=mx+b
9x+5y=23
5y=-9x+23
y=-9/5x+23/5
m=slope: -9/5
b=y-intercept: 23/5
You can eliminate 81 because we know 
The dot is on approximately 9.32 (my estimate) so I would square that number:
(9.32)² = 86.8624 so if you round this you get 87