If the sin 30° = , then the cos 60° = 0, because the angles are complementary , because the angles are complementary , because the angles are complementary 1, because the angles are complementary

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?