Angle D is equal to Angle B because AB and DE are parallel to each other.
AD is a straight line so the (2) 2x angles and 72 degrees need to equal 180.
Setting up the equation you have:
2x + 2x + 72 = 180
Simplify:
4x + 72 = 180
Subtract 72 from each side:
4x = 108
Divide both sides by 4:
x = 108 / 4
x = 27
Answer:


Step-by-step explanation:
Given

--- lower diameter
--- upper diameter
Solving (a): The curved surface area
This is calculated as:

Where
--- lower radius
--- upper radius
And
---- l represents the slant height of the frustrum





So, we have:




Solving (b): The volume
This is calculated as:

This gives:





When you've got a squares bracket, this simply becomes the bracket twice, therefore, (r+s)2 becomes (r+s)(r+s)
You've then go to use FOIL, and this gives you r^2+rs+sr+s^2, and this cannot be simplified any further.
Therefore, the product of this is r^2 + s^2 + rs + sr
Hope this is what you're looking for :)
Yes you did it correctly but change problem 5’s denominator on the right to a 6