Final answer:
The density of the rectangular solid is 2.79 g/cm³, calculated by dividing the mass by the volume of the solid. The density of the irregular solid is 0.164 g/cm³, found by using water displacement to measure its volume and dividing the mass by this volume.
Step-by-step explanation:
To find the density of a rectangular solid, we use the formula density = mass/volume. The volume of a rectangular solid is found by multiplying its length, width, and height. Therefore, the volume of the given solid is 4.5 cm x 2.5 cm x 1.5 cm = 16.875 cm³. To find the density, we divide the mass by the volume, so the density = 47.12 g / 16.875 cm³ = 2.79 g/cm³.
For the irregular solid, when displacement is used to measure volume, the volume of the solid is the difference between the final and initial volumes of water. Thus, the volume of the solid is 25.7 mL - 18.4 mL = 7.3 mL. To convert milliliters to cubic centimeters (assuming 1 mL = 1 cm³), the volume is 7.3 cm³. The density of the solid is then calculated as mass divided by volume: 1.2 g / 7.3 cm³ = 0.164 g/cm³.