SOLUTION: In Isosceles trapezoid ABCD, the longer base, AB, is one and one half as long as the shorter bse, CD. The other two sides, AD and BC are both 13cm long. If the perimeter is 76c

Algebra ->  Expressions-with-variables -> SOLUTION: In Isosceles trapezoid ABCD, the longer base, AB, is one and one half as long as the shorter bse, CD. The other two sides, AD and BC are both 13cm long. If the perimeter is 76c      Log On


   



Question 234880: In Isosceles trapezoid ABCD, the longer base, AB, is one and one half as long as the shorter bse, CD. The other two sides, AD and BC are both 13cm long.
If the perimeter is 76cm, find the lengths of AB and CD.

Answer by Stitch(470) About Me  (Show Source):
You can put this solution on YOUR website!
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+%2B+BC+%2B+CD+%2B+AD Place 13cm in for AD & BC
76cm+=+AB+%2B+13cm+%2B+CD+%2B+13cm Combine like terms
76cm+=+AB+%2B+CD+%2B+26cmSubtract 26cm from both sides
50cm+=+AB+%2B+CD Now it is time to substitute the 1.5*(CD) for AB
50cm+=+1.5%2A%28CD%29+%2B+CD rewrite the equation
50cm+=+2.5%2A%28CD%29 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%2A20cm
AB+=+30cm