$r=6
\\d=2r=12
\\PQ=QR=RS= \frac{d}{3} = \frac{12}{3} =4
\\
\\P= \frac{1}{2}\times 2r\pi+\frac{1}{2}\times 2\times QR\times\pi+\frac{1}{2}\times 2 \frac{PQ}{2} \pi
\\
\\P=r\pi+QR\times\pi+\frac{PQ}{2} \pi
\\
\\P=6\pi+4\pi+\frac{4}{2} \pi
\\
\\P=12\pi$

4 0

3 years ago

A school bus has 25 seats, with 5 rows of 5 seats. 15 students from the first grade and 5 students from the second grade travel

kow [346]

Answer:

5P5×20P15

Step-by-step explanation:

A school bus has 25 seats, with 5 rows of 5 seats.

15 students from the first grade and 5 students from the second grade travel in the bus.

second-grade students occupy the first row.

The 5 students of second grade are to be seated in 5 seats,this can be done in:

5P5 ways where P is the permutation

Now 15 students from first grade are to be arranged in remaining 20 seats

This can be done in:

20P15 ways

Hence, total ways student can be seated is:

5P5×20P15

6 0

3 years ago