Final answer:
To find the length of each part of the wood when it is divided in the ratio 7:2, divide the total length by the sum of the parts.
Step-by-step explanation:
To find the length of each part of the wood, we first need to determine the total number of parts into which the length is divided. The ratio of the lengths is given as 7:2, which means there are 7 parts of the length for the first portion and 2 parts for the second portion.
To find the length of each part, we divide the total length by the sum of the parts. In this case, we divide 45 cm by 7+2=9.
So, each part of the wood is 45 cm / 9 = 5 cm long.