how do I solve with dimensional analysis?

1111111 6. An adequate blood level of vitamin D is 20.0 ng/mL. What is this level in Ib/in? 7. The recommended daily allowance (RDA) of calcium is 1.2 9. Calcium carbonate contains 12.0% calcium by mass. How many grams of calcium carbonate are needed to provide the RDA of calcium? Review percent by mass. You must use DA, as on all problems. 8. One of the common intravenous fluids, called physiological saline, is a homogeneous mixture of NaCl in water. In this mixture, 0.89% of the mass is contributed by the NaCl. What mass of NaCl is found in 655.0 mL of physiological saline? (Given: density of physiological saline = 1.005 g/cm)