Find the sides of the parallelogram ABCD if its perimeter is 80 cm and the sides AB are more than BC by 5 cm.

Given:
ABCD – parallelogram,
AB – BC = 5 centimeters,
the ABCD perimeter is 80 centimeters.
Find the lengths of the sides of the parallelogram ABCD: AB, CD, BC, AD -?
Solution:
Consider a parallelogram ABCD. Its opposite sides are equal to each other, then BC = AD, AB = CD.
Let the length of the BC side be x centimeters, then the length of the AB side = 5 + x centimeters. We know that the ABCD perimeter is 80 centimeters. Let’s make the equation:
P avce = AB + CD + BC + AD;
80 = 5 + x + 5 + x + 5+ x + x;
4 * x = 80 – 10;
4 * x = 70;
x = 70: 4;
x = 17.5 centimeters – the lengths of the sides BC and AD;
17.5 + 5 = 22.5 centimeters – the lengths of the sides AB and CD.
Answer: 17.5 centimeters; 17.5 centimeters; 22.5 centimeters; 22.5 centimeters.