9. The ticket at right has a perimeter of 42 cm. a) Calculate the unknown side length.
A = 42 - 11 x 2 = 20 / 4 = 5
b) Olivia wishes to decorate the ticket by placing a
gold line along the slanted sides. How long is the line on each ticket?
A =
c) A bottle of gold ink will supply enough ink to draw 20 m of line. How many bottles of ink should be purchased if 200 tickets are to be decorated?
A =

Perimeter simply represents the sum of all side lengths of a shape. The length of the missing side of the ticket is 5 cm; the length of gold line on each ticket is 20 cm, and 2 bottles of gold ink are required to draw gold lines on 200 tickets.

I've added the image of the ticket as an attachment.

(a) The missing side length

From the attachment, the 4 unknown side lengths are equal. Represent this side length with L.

So, we have:

This gives

Collect like terms

Divide both sides by 4

(b) The length of the gold lines

There are 4 slant lines and the length of one of the slant lines is 5 cm (as calculated above).

So, the length of the gold line is:

(c) The number of gold ink bottles.

--- number of tickets

The length of all gold line in the 200 tickets is:

---- convert to meters

Given that:

--- 1 bottle for 20 m

The number of bottles (n) is:

Hence, 2 bottles of gold ink are enough.

Read more about perimeters at: