We have been given that the standard deviation of a group of 20 scores is 15 and we are asked to find variance.
Since we know variance is square of standard deviation. In order to find out the variance of the given data we have to take the square of 15.

Therefore, our variance is 225.
Answer:
x = 3
Step-by-step explanation:
ΔABC is 45 45 90 right triangle
The ratio of leg: hypo = a : a√2
Given: hypo AC = 6√2; so AB = BC = 6
ΔBCD is 30 60 90 right triangle
The ratio of short leg : long leg : hypo = x : x√3 : 2x
Hypo. BC = 6 = 2 (3)
So short leg BD = x = 3
Answer:
C
Step-by-step explanation:
The secant- tangent angle MLK is half the difference of the intercepted arcs, that is
(KN - KM) = 70° ( multiply both sides by 2 to clear the fraction )
KN - KM = 140°
KN - 61° = 140° ( add 61° to both sides )
KN = 201° → C