Let
be the random variable for the number of marks a given student receives on the exam.
10% of students obtain more than 75 marks, so

where
follows a standard normal distribution. The critical value for an upper-tail probability of 10% is

where
denotes the CDF of
, and
denotes the inverse CDF. We have

Similarly, because 20% of students obtain less than 40 marks, we have

so that

Then
are such that


and we find

The answer is: 12 centimeters.
The explanation is shown below:
1. By definition, all four sides of the square are equal and the diagonals are equal too.
2. Keeping the information above on mind, you know that AC and BD are equal:

3. Then, the length of BD is twice BE. So, you can calculate it as following:


4. Therefore, the lenght of AC is:

The area would be approximately 153.94.
The area of a circle is pie multiplied by r^2.
So you have the radius, which is r. Plug in r. Technically you have two numbers because pie equals approximately 3.14.
A=3.14(7)^2
Answer:
0.6 over 0.6. Or just 1.
Step-by-step explanation:
Step-by-step explanation:
as diameter=50 yards
radius (r)=50/2=25 yards
ar of circle = π r r
π=22/7
22÷7×25×25
1974.285714