Given that figure ABCD is a parallelogram and that the length of DE is one-third the length of AD. What is the perimeter of parallelogram ABCD?
Label one side "a" and the other "b", then:
Perimeter =2 x [a + b] . Now, you have to make sure that one side is 1/3 of the other. So, if "a" is 1 meter, then "b" will be 1/3a. So the formula will become:
Perimeter =2 x [a + 1/3a] =2 x [1 + 1/3*1] =2 x [1 1/3] =2 x 4/3 =8/3 =2 2/3 meters.
