Answer:
42 cm
Explanation:
An equilateral triangle has 3 equal sides.
Thus,
x +8= y +4
x= y+4 -8
x= y -4 -----(1)
4x-y= y+4
4x= y +y +4 (+y on both sides)
4x= 2y +4 (simplify)
Divide by 2 throughout,
2x= y +2 -----(2)
subst. (1) into (2):
2(y -4)= y +2
2(y) +2(-4)= y +2 (expand)
2y -8= y +2
2y -y= 8 +2
y= 10
Length of a side of the traingle
= y +4
= 10 +4
= 14
Perimeter of triangle
= 3(14)
= 42 cm