The length of a rectangle is three times as long as its width. The width of this rectangle is 6 inches smaller than its length. Find the length and the width. (It would also be interesting to know its area and perimeter!)

The length is 9in and the width is 3in

The perimeter is 24in and the area is 27in²

Step-by-step explanation:

To start we have to make 2 equations with the information that gave us the problem

l = length

w = width

w = l - 6in

l = 3w

we replace l in the first equation with (3w)

w = (3w) - 6in

w - 3w = -6in

-2w = -6in

w = -6in / (-2)

w = 3in

now we replace the value of w in the second equation

l = 3w

l = 3 (3in)

l = 9in

Now that we have the length and width we can calculate the perimeter and the area with the following formulas

p = perimeter

a = area

p = 2w + 2h

p = 2(3in) + 2(9in)

p = 6in + 18in

p = 24in

a = w * l

a = 3in * 9in

a = 27in²

, and

for

step-by-step explanation:

we can analyze the pattern at which the terms increase. let us denote , , , so that we can call

note the following:

the pattern: to get the next term value, we just add the next term number (e.g. 1st, 2nd, to the previous term value (term values are the given numbers in the question, 1, 3, 6, 10, 15,

from , to get to , we add

from , to get to , we add

etc.

we need to form a recursive formula, a formula that has the next term as a function of the previous term. so a possible recursive formula can be

, and for

3

step-by-step explanation: