If the pieces are cut in the ratio 3:5:7, the proportion of each piece to the whole (represented by 3+5+7=15) is:
3/15:5/15:7/15
First, convert the inches to feet also:
1 foot equals to 12 inches.
So 9 inches =9/12×1=0.75 feet.
Thus, 33 feet and 9 inches equal 33+0.75=33.75 feet.
So,
P=3/15×33.75=6.75 feet.
Q=5/15×33.75=11.25 feet.
R=7/15×33.75=15.75 feet.
You can check that these answers are correct by adding up the different pieces: 6.75+11.25+15.75=33.75