In an arithmetic progression the sum of the fifth and sixth terms is 44 and the sum of the first eighteen terms is thrice the sum of the first ten terms, find the value of the

a = 5.5, d = 11/3

Step-by-step explanation:

An arithmetic progression is a sequence of number such that the difference between consecutive numbers is a constant. It is given by:

The sum of fifth and sixth terms is 44

Therefore:

a + 4d + a + 5d = 44

2a + 9d = 44                       (1)

The sum of the first n terms is:

Since the sum of the first eighteen terms is thrice the sum of the first ten terms:

18a + 153d = 3(10a + 45d)

18 a + 153d = 30a + 135d

18a  - 30a + 153d - 135d = 0

-12a + 18d = 0                    (2)

Multiply equation 1 by 6 and add to equation 2:

72d = 264

d = 11/3

Putting d = 11/3 in eqn 2

-12a + 18(11/3) = 0

-12a + 66 = 0

12a = 66

a = 5.5

the figures below are made out of circles, semicircles, quarter … find the area and the perimeter of each figure and give your answers as a completely simplified exact value in terms of π (no approximations). remember that we'll also have to cut whatever areas we get in half, since we're only dealing im pretty sure that is the right answer

step-by-step explanation: