Answer:
$450
Step-by-step explanation:
First of all, you need to find the area of the triangle. The formula is:
Area of triangle = 1/2 * base * height
Given the base of triangle is 5m and the height is 10m. So, the area of triangle will be:
Area of triangle = 1/2 * 5m * 10m
Area of triangle = 25 meter square
Then, you can find the cost of canvas to make a sail.
Cost = $18 * 25 meter square
Cost = $450
Thus, the cost of canvas to make a sail is $450.