Answer:
the standard deviation of the speeds of cars travelling on California freeways is 6.0 miles per hour
Step-by-step explanation:
The computation of the standard deviation of the speeds of cars is shown below;
The z score for the top 1% is 2.326
So,
= (75 - 61) ÷ standard deviation = 2.326
Standard deviation is
= 14 ÷ 2.326
= 6.0 miles per hour
Hence, the standard deviation of the speeds of cars travelling on California freeways is 6.0 miles per hour
First step: name the sides according to geometry standards, namely, the sides are named the same lowercase letter as the opposing angle. A revised diagram is shown.
Second step: we need to know the relationships of the trigonometric functions.
cosine(A)=cos(63) = adjacent / hypotenuse = AC/AB .................(1)
sine(A)=sin(63) = opposite / hypotenuse = CB/AB .......................(2)
We're given AB=7, so
using (1)
AC/AB=cos(63)
AC=ABcos(63)=7 cos(63) = 7*0.45399 = 3.17993 = 3.180 (to three dec. figures)
Using (2)
BC/AB=sin(63)
BC=ABsin(63) = 7 sin(63) = 7*0.89101 = 6.237 (to three dec. figures).
