Answer:
r=(A/π)^1/2
Step-by-step explanation:
A=πr^2. When dividing π on both sides, you get r^2 = A/π. Meaning that r = the square root of A/π, or (A/π)^1/2
Answer:
161
Step-by-step explanation:
the sum of the two interior angles equals that exterior angle
121+40=161
Answer:
The probability that a call last between 4.2 and 4.9 minutes is 0.4599
Step-by-step explanation:
Let X be the length in minutes of a random phone call. X is a normal distribution with mean λ=4.2 and standard deviation σ=0.4. We want to know P(4.2 < X < 4.9). In order to make computations, we will use W, the standarization of X, given by the following formula

We will use
, the cummulative distribution function of W. The values of
are well known and the can be found in the attached file

We conclude that the probability that a call last between 4.2 and 4.9 minutes is 0.4599
0 -18 is the answer to your question