Answer:
a = 9.849
b = 20.25
c = 491.03
Step-by-step explanation:
By using Pythagoras theorem in the right triangle BDC,
(Hypotenuse)² = (Leg 1)² + (Leg 2)²
BC² = BD² + DC²
a² = 9² + 4²
a = 
a = 
a = 9.8489
a ≈ 9.849 units
By mean proportional theorem,

AD × DC = BD²
b × 4 = 9²
b = 
b = 20.25 units
BY Pythagoras theorem in ΔADB,
AB² = AD² + BD²
c² = b² + 9²
c² = (20.25)² + 9²
c² = 410.0625 + 81
c = 491.0625
c = 491. 063 units
Max amount of people who can attend is 10.
200-160=40
40 ÷4= 10
Answer:
a) 2.5% b) 50%
Step-by-step explanation:
1300 is two standard deviations higher than the mean. Since 95% of the data is covered within two standard deviations to the left and right of the mean, 5% is not covered. So, we have 2.5% leftover on the left side of the curve, under 900, and 2.5% leftover on the right side of the graph that is above 1300.
The mean is 1100, so anything above or below the mean is exactly 50% in a normal distribution.