Answer:
(53.812 ; 58.188) ; 156
Step-by-step explanation:
Given that :
Sample size (n) = 51
Mean (m) = 56
Standard deviation (σ) = 9.5
α = 90%
Using the relation :
Confidence interval = mean ± Error
Error = Zcritical * (standard deviation / sqrt (n))
Zcritical at 90% = 1.645
Error = 1.645 * (9.5 / sqrt(51))
Error = 1.645 * 1.3302660
Error = 2.1882877
Hence,
Confidence interval :
Lower boundary = 56 - 2.1882877 = 53.8117123
Upper boundary = 56 + 2.1882877 = 58.1882877
Confidence interval = (53.812 ; 58.188)
2.)
Margin of Error (ME) = 1.25
α = 90%
Sample size = ((Zcritical * σ) / ME)^2
Zcritical at 90% = 1.645
Sample size = ((1.645 * 9.5) / 1.25)^2
Sample size = (15.6275 / 1.25)^2
Sample size = 12.502^2 = 156.3000
Sample size = 156
Answer:
Look below
Step-by-step explanation:
Given that CDB is 90 degrees, ACB is 90 degrees, and ACD is 60 degrees, we can determine that DCB = 90-60 = 30 degrees.
This means triangle BCD is a 30-60-90 (angle measures) right triangle
The proportions of the sides (from smallest to largest) is
x:x√3:2x
We are given that BC = 6 cm. This means...
2x=6
x=3
This means DB is 3 cm and CD is 3√3 cm
Using the linear pair theorem, we can find that Angle CDA is 90 degrees. This means ACD is also a 30-60-90 triangle.
x=3√3
x√3=9
2x=6√3
Now we need to find AB
AB = AD + DB
AB = 9 + 3
AB = 12 cm

Answer:
(4,4)
Step-by-step explanation:
1. I drew a grid and plotted the 3 points I already knew
2. I found the spot that had the same x coordinate that the point to the bottom left of the shape, and the same y coordinate of the top right of the shape which was the point (4,4)
I hope this helps!!