Step-by-step explanation
firstly the units are not consistent
what will need to do now is to convert 42 inches to ft
by converting 42 inches into ft, we will have a consistent units and also easy to divide
Let start by converting
1 ft ----- 12inches
x ft ------ 42 inches
introduce cross multiplication
xft * 12inches = 1ft * 42inches
make x ft the subject of the formula by dividing the equation through 12
x = 42 / 12
42 and 12 both have a common factor of 6, therefore 42 and 12 are divisible by 6
x = 7 / 2
42 inches is equivalent to 7 /2 ft
the ratio of 3ft to 7 /2 ft is
3ft : 7 / 2ft
3 divided by 7/2
the division sign will change to multiplication when will interchange the denominator and numerator of the right fraction
= 3 * 2/7
= 6/7
the answer is 6/7