The perimeter of a rectangle is 86 in. The with is 25 in. What is y?

Question

This question is simple but also very hard for very few people. Answer this in the nick of time. 

Answer 1

Good morning, Ashley,

Let's solve the problem in the following manner, okay? 

Normally, I would use L to represent the length, but as you know in Algebra, you can exchange one expression of like value for another. In this case, we are merely going to establish from the outset, that when I solve for L, I am solving for y. Fair enough? 

W = 25           L or y = Length     Perimeter = 86     

P = 2 (L + W)   

This equation simplifies the above:

P/2 = L + 25                                                     

Therefore, given what we know: 

Plugging in values to begin solving.

(P/2)-W = L 

Now, we can solve, correct? 



(86/2) - 25 = L

 

43 - 25 = L 

 

18 = L

Now, check or proof our work, because we always want to do this when solving problems, okay?

 

P = 2 (L + W) 

86 = 2 (x + 25)       I have now substituted x for L 

86 = 2 (18 + 25)

 

86 = 2 (43)

86 = 86 

Therefore, given the problem presented we now know:

Perimeter = 86 

Length or y = 18

Width or W = 25 


I hope this helps and that you have a great weekend. Please let me know whether the answer makes sense in the comments section below.