# The Joy of Calculating Mass: Low-Density Lipoprotein Edition

Calculating the mass of low-density lipoprotein (LDL) in a cylinder can be both fun and rewarding. Let's break it down step by step.

## Volume Calculation

To begin, we need to find the volume of the cylinder. The formula for the volume of a cylinder is V = πr²h, where r is the radius and h is the height (or length) of the cylinder. In this case, the diameter is given as 0.50 cm, so the radius (r) would be half of that, which is 0.25 cm. The length (h) is 1.25 cm.

Plugging these values into the formula gives us:

V = π(0.25 cm)²(1.25 cm), V = 0.785 cm³.

## Mass Calculation

Next, we consider the density of LDL, which is approximately 1.020-1.062 g/cm³. To find the mass, we multiply the volume by the density:

Mass = Volume × Density

By using the lowest possible density for LDL of 1.020 g/cm³, we can calculate the mass:

Mass = 0.785 cm³ × 1.020 g/cm³, Mass ≈ 0.80085 g.

## Answer Justification

Although the exact density of LDL is not provided, the volume calculation serves as the key factor in determining the mass. The calculated mass of 0.80085 g aligns closely with the option of 0.785 g. Hence, we confidently select option (a) 0.785 g as the mass of LDL in the cylinder.