Question

The length, breadth and height of a room are $12m,15m$ and $18m$ respectively. Determine the longest tape which can measure all the three dimensions of the room exactly.

Answer 1

HCF of $12,15,18$ will be the longest tape measure.

$12=3\times 4=3\times 2\times 2$

$15=3\times 5$

$18=9\times 2=3\times 3\times 2$

highest common factor is $3$

Therefore HCF of $12,15,18$ is $3$

$\therefore 3m$ is the longest tape measure which can measure all the dimensions.