Which equation is correct regarding the measure of Z1?
OmZ1 = (a-c)
m_1= {(a+c)
m21= {(6-0)
O m21= {(6+0)

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?