Question

figure cdef is a parallelogram. what is the value of r? 2 3 4 5

Explanation:

Step1: Use the property of parallelogram

In a parallelogram, opposite sides are equal. So, \(CF = DE\).
Given \(CF=10r - 20\) and \(DE = 6r\). Then \(10r-20=6r\).

Step2: Solve the equation

Subtract \(6r\) from both sides: \(10r-6r - 20=6r-6r\), which gives \(4r-20 = 0\).
Add \(20\) to both sides: \(4r-20 + 20=0 + 20\), so \(4r=20\).
Divide both sides by \(4\): \(r=\frac{20}{4}=5\).

Answer:

\(5\)