Two adjacent angles of a parallelogram are in the ratio 4:5. Find the measure of measure of each of its angles.
What does ratio 4:5 mean? How do we set up the problem to solve for the angles?
A ratio of 4:5 signifies 4 + 5, or 9 parts
Adjacent angles of a parallelogram are congruent
Method 1:
Therefore, smaller angle is: , and larger angle is: , or
OR
Method 2:
Equation: 4x + 5x = 180
Solve for x, the multiplicative factor
Multiply value of x by 4 to get smaller angle
Multiply value of x by 5, or subtract smaller angle from 180 to get larger angle
Both methods should provide same results.