Question $3(10$ marks$)$

You used a large piece of canvas that was in your garage to create a makeshift roof at a braai you were hosting. Because you neglected to keep the material far enough from the flames, the material caught fire and a large section of it burned away. Turns out the canvas was part of your cousin's hot air balloon. You are now responsible for replacing the material based on the sketch your cousin provided:

$($a$)$ Calculate the area of canvas you would need to purchase. $($Remember there is an opening in the canvas above the basket to allow the propane flame that heats the air in the balloon, through$)$

$($b$)$ As you are now invested into the hot air balloon and how it works $-$ you wonder how much air it takes to fill such and air balloon. Calculate the volume of air inside the balloon.