Question 234880
Given:
Total perimeter = 76cm = AB + BC + CD + AD
AD & BC = 13cm
AB = 1.5*(CD)
Solution:
Since we know AD & BC are both 13cm long, plug those numbers into the perimeter equation
{{{76cm = AB + BC + CD + AD}}} Place 13cm in for AD & BC
{{{76cm = AB + 13cm + CD + 13cm}}} Combine like terms
{{{76cm = AB + CD + 26cm}}}Subtract 26cm from both sides
{{{50cm = AB + CD}}} Now it is time to substitute the 1.5*(CD) for AB
{{{50cm = 1.5*(CD) + CD}}}  rewrite the equation
{{{50cm = 2.5*(CD)}}} Divide both sides by 2.5
{{{20cm = CD}}}
To find AB, plug 20cm in for CD in the equation AB = 1.5*(CD)
{{{AB = 1.5*20cm}}}
{{{AB = 30cm}}}