X = 180 - (y+z)
x = 180 (60+80)
x = 180 -140
x = 40
The average can be found by adding them all up and dividing that number by the number of items. If the result have you a number that's more than the largest or less than the lowest, you did it wrong.
(75+70+90+60+50+90+70)/7
= 505/7
=72.14
The correct answer is x = 20
If the area is 120, each length is root(120)
root(120) = 2*root(30)
so the perimeter is:
4 * 2 * root(30) = 8 root(30)
which is approximately 43.8
