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.
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Answer:
C
Step-by-step explanation:
There can be multiple solutions when two lines intersect.
If you multiply 2x2 you get 4 and multiply another 2 which is 8. Two answers are 8 and 2x2x2.
Each curve completes one loop over the interval

. Find the intersections of the curves within this interval.

The region of interest has an area given by the double integral

equivalent to the single integral

which evaluates to

.
Answer:
7. 1520.53 cm²
8. 232.35 ft²
9. 706.86 m²
10. 4,156.32 mm²
11. 780.46 m²
12. 1,847.25 mi²
Step-by-step explanation:
Recall:
Surface area of sphere = 4πr²
Surface area of hemisphere = 2πr² + πr²
7. r = 11 cm
Plug in the value into the appropriate formula
Surface area of the sphere = 4*π*11² = 1520.53 cm² (nearest tenth)
8. r = ½(8.6) = 4.3 ft
Plug in the value into the appropriate formula
Surface area of the sphere = 4*π*4.3² = 232.35 ft² (nearest tenth)
9. r = ½(15) = 7.5 m
Surface area of the sphere = 4*π*7.5² = 706.86 m² (nearest tenth)
10. r = ½(42) = 21 mm
Plug in the value into the formula
Surface area of hemisphere = 2*π*21² + π*21² = 2,770.88 + 1,385.44
= 4,156.32 mm²
11. r = 9.1 m
Plug in the value into the formula
Surface area of hemisphere = 2*π*9.1² + π*9.1² = 520.31 + 260.15
= 780.46 m²
12. r = 14 mi
Plug in the value into the formula
Surface area of hemisphere = 2*π*14² + π*14² = 1,231.50 + 615.75
= 1,847.25 mi²