1. 208/x = 100/130
2. multiply both sides by x
3. 208 = 0.76923x
4. divide both sides by 0.76923
5. x = 270.4
Answer:
The number of observations is 15.
F(x) = x^2 + 1
f(4) = 4^2 + 1 = 16 + 1 = 17
2*f(4) = 2 * 16 = 32
500 = 10x + 2 * 15 * 5 + 15x
500 = 25x + 150
500 - 150 = 25x
350 = 25x
x = 14
Triangular ends: 14 * 10 = 140
Base rectangle: 14 * 15 = 210
side rectangles: 5 * 15 * 2 = 150
140 + 210 + 150 =