Final answer:
To find the number of leads of side 5mm that can be made from a rectangular block of lead, calculate the volume of the block and divide it by the volume of each lead.
Step-by-step explanation:
To find the number of lead of side 5mm that can be made from a rectangular block of lead measuring 10cm by 5cm by 4cm, we need to calculate the volume of the block and then divide it by the volume of each lead.
The volume of the block is calculated by multiplying its length, width, and height: 10cm × 5cm × 4cm = 200cm³.
The volume of each lead is calculated by multiplying the side length by itself twice: 5mm × 5mm × 5mm = 125mm³. However, we need to convert the side length to centimeters since the block's dimensions are in centimeters. 1cm = 10mm, so 5mm = 0.5cm.
Therefore, the volume of each lead is 0.5cm × 0.5cm × 0.5cm = 0.125cm³.
To find the number of leads, we divide the volume of the block by the volume of each lead: 200cm³ ÷ 0.125cm³ = 1600.
Therefore, you can make 1600 lead of side 5mm from the rectangular block of lead.