Full circle
Circumference = 2*pi * r
Circumference = pi * d
Area = pi r * r = pi * r^2
Area = pi d^2 / 4
Half circle
Circumference = pi * r
Circumference = pi * r / 2
Area = pi r^2 / 2
Area = pi d^2/8
The answer depends on what you are looking for and what you are given. But those are the only common formulas I can think of at the moment.
For 3 it’s b. For 2 it’s 8. For 4 it’s the whole number
Answer:
Now, add these two equations.
You get,
Given,
You can test this to the other equation as well.
Hence, the two numbers are 14 and 10.
Somebody can estimate the length of a book by using a ruler and rounding it to the nearest whole number.
First I am going to assume that these are both right triangles based off of look and because it is much easier. Without it you have to use law of sines or law of cosines...
So to find x you must first find y which can be done simply by using the pythagorean theorem. This theorem is defined as the sum of the squared legs is equal to the sum of the hypotenuse or x^2 + y^2 = z^2
If we substitute in the known values 16^2 + y^2 = 20^2 and solve for y we get that y = sqrt(20^2 - 16^2), this then simplifies to y = 12
Finding x is much more annoying, the easiest way I can immediately see is to find the upper angles by doing sin(16/20) and then 90 - sin(16/20) since the complementary angle is the one you want. I don't have a calculator or a trig table with me right now but I will tell you that x will be equal to 12 ÷ the inverse cosine of the angle (90degrees - sin(16/20)).
I am pretty sure the answer is D though because we know for sure y = 12 and x has to be greater than y because the hypotenuse must be larger than both legs. It could be E but you won't know unless you do the math for x. So it is either D or E but I would be surprised if a Professor made you do all of the work just to say it doesn't work...
