To find it directly
A = 2 pi r h
A is proportional to rh
factor 2
A is multiplied by 2 * 2 = 4
factor 3
3 * 3 =9
factor 5
5 * 5 = 25
factor 10
10 * 10 = 100
(b) the increase in A by factor x is x^2
c(20)^2 = 400
Since b = c, the angles B and C are congruent.
180 - 45 = 135
135/2 = =67.5
A = 45
B = 67.5
C = 67.5
a = ?
b = 4
c = 4
Since we know two sides and all three angles, we can use the law of sines to find a.
b/sin B = a/sin A
4/(sin 67.5) = a/(sin 45)
a = 4(sin 45)/(sin 67.5)
a^2 = (4(sin 45)/(sin 67.5))^2
a^2 = 9.37
1. Move the negative sign to the left.
- 
*-50
2. Use this rule: 
=
-
3. Simplify - 
4. Move the negative sign to the left.
-(-950x/8)
5. Simplify 950x/8 to 475x/4
6. Remove parentheses.
I believe the range is 25.
