This is the concept of areas of solid materials; the surface area of the cylinder whose radius is 2.5 cm and lateral area is 20 pi cm^2 will be: Surface area of cylinder is given by: SA=(area of cyclic sides)+(lateral area) SA=2πr^2+πrl Area of the cyclic sides will be: Area=2πr^2 =2*π*2.5^2 =12.5π cm^2 The lateral area is given by: Area=20π cm^2 Therefore the surface area of cylinder will be: SA=(12.5π+20π) cm^2 SA=32.5π cm^2 The answer is 32.5π cm^2
If you plug in 7 for n, you get (7+1)(7-2). Simplify that. (8)(5) Simplify that and you get the 7th term of the particular sequence is, 40 Hope it helps :D
