Answer:

Step-by-step explanation:
Given
The attached triangle
Required
Find cos V
In trigonometry:

In this case:

Where

and
-- Pythagoras


Take square roots




So:



Rationalize:


Find the area of the fabric
The fabric is circular, so we find the area using the area of circle formula
a = π × r²
input the numbers
a = π × r²
a = 3.14 × (1.2)²
a = 3.14 × 1.44
a = 4.5216 ft²
Calculate the total cost
Multiply the cost by the area
cost = 5.4 × 4.5216
cost = 24.417
The total cost is approximately $24.42