Can anyone me ?
which expression can be used to find the area of a circle with a diameter of 30 cm?

a. π • 30

b. 2 • π • 15

c. π • 30^2

d. π • 15^2

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?