Divide 872/638,304 please help me

Olivia uses the work below to determine 55% of 720 which explains the error in olivia’s solution

Look at the figure below: triangle abc is a right triangle with angle abc equal to 90 degrees. the length of ac is 5 units and the length of ab is 4 units. d is a point above c. triangle adc is a right triangle with angle dac equal to 90 degrees and dc parallel to ab. what is the length, in units, of segment cd?

Solve for the equation x. 2x + 22 = 4(x + 3)