The teacher will use 3 rolls only to have perfect measurements.
1 yard = 3 feet
4 large bulletin boards are there each needing 9 yards of border.
That means 4 large bulletin boards in total need
9×4 yards of border
= 36 yards of border
= 108 feet of border
Also, there is a small bulletin board that only needs 12 feet border
Hence, in total there is a need for
108 + 12 = 120 feet border.
The border is sold in 40-foot rolls.
Hence, there is a need for 120/40 rolls
i.e. 3 rolls
Hence, the teacher will use 3 rolls only.
Learn more about measurements here-
brainly.com/question/15658113
#SPJ10
