18/4ths, 27/6ths, and 36/8ths.
Hi there!
When two lines intersect, we know that the ones on the opposite sides are equal to one another. Thus, we know that the angle opposite of the one marked with 90 degrees (on the other side of the intersection) is also 90 degrees.
We know that a full turn is 360 degrees. We can see that the two 90 degrees make up part of the turn, and the other pair of angles, both of which are equal to x (as per the reasoning above), make up the rest. We know that the two 90 degrees, added together, is equal to 180 degrees. This means, after subtracting 180 from 360, that 180 degrees are remaining that aren't the 2 90 degrees, and are make up of two angles both measuring x degrees.
As we know that they both measure x, then we know that we say 2x = 180, which gives us x = 90.
Hope this helps!
Answer:
2. Not enough information
4. Congruent SAS
4. Similar, not enough information to determine congruency.
Step-by-step explanation:
2. We only know one side and one angle are congruent, Not enough to determine congruency
4. We know two sides and the angle between are vertical angles and vertical angles are congruent. SAS is how the triangles are congruent.
6. The three angles are congruent which makes the triangles similar. We need to know a side if they are to be congruent
Answer:
It'll take 38.3 years to obtain the desired return of $25,000.
Step-by-step explanation:
In order to solve a continuosly coumponded interest question we need to apply the correct formula that is given bellow:
M = C*e^(r*t)
Where M is the final value, C is the initial value, r is the interest rate and t is the time at which the money was applied. Since he wants an return of $25,000 his final value must be the sum of the initial value with the desired return. So we have:
(25000 + 8000) = 8000*e^(0.037*t)
33000 = 8000*e^(0.037*t)
e^(0.037*t) = 33000/8000
e^(0.037*t) = 4.125
ln[e^(0.037*t)] = ln(4.125)
t = ln(4.125)/(0.037)
t = 1.4171/0.037 = 38.2991
t = 38.3 years
Adding 2 to each value of the random variable 
makes a new random variable 
. Its mean would be
![E[X+2]=E[X]+E[2]=E[X]+2](https://tex.z-dn.net/?f=E%5BX%2B2%5D%3DE%5BX%5D%2BE%5B2%5D%3DE%5BX%5D%2B2)
since expectation is linear, and the expected value of a constant is that constant. ![E[X]](https://tex.z-dn.net/?f=E%5BX%5D)
is the mean of , so the new mean would be
![E[X+2]=10+2=12](https://tex.z-dn.net/?f=E%5BX%2B2%5D%3D10%2B2%3D12)
The variance of a random variable is
![V[X]=E[X^2]-E[X]^2](https://tex.z-dn.net/?f=V%5BX%5D%3DE%5BX%5E2%5D-E%5BX%5D%5E2)
so the variance of would be
![V[X+2]=E[(X+2)^2]-E[X+2]^2](https://tex.z-dn.net/?f=V%5BX%2B2%5D%3DE%5B%28X%2B2%29%5E2%5D-E%5BX%2B2%5D%5E2)
We already know ![E[X+2]=12](https://tex.z-dn.net/?f=E%5BX%2B2%5D%3D12)
, so simplifying above, we get
![V[X+2]=E[X^2+4X+4]-12^2](https://tex.z-dn.net/?f=V%5BX%2B2%5D%3DE%5BX%5E2%2B4X%2B4%5D-12%5E2)
![V[X+2]=E[X^2]+4E[X]+4-12^2](https://tex.z-dn.net/?f=V%5BX%2B2%5D%3DE%5BX%5E2%5D%2B4E%5BX%5D%2B4-12%5E2)
![V[X+2]=(V[X]+E[X]^2)+4E[X]-140](https://tex.z-dn.net/?f=V%5BX%2B2%5D%3D%28V%5BX%5D%2BE%5BX%5D%5E2%29%2B4E%5BX%5D-140)
Standard deviation is the square root of variance, so ![V[X]=3^2=9](https://tex.z-dn.net/?f=V%5BX%5D%3D3%5E2%3D9)
.
![\implies V[X+2]=(9+10^2)+4(10)-140=9](https://tex.z-dn.net/?f=%5Cimplies%20V%5BX%2B2%5D%3D%289%2B10%5E2%29%2B4%2810%29-140%3D9)
so the standard deviation remains unchanged at 3.
NB: More generally, the variance of 
for 
is
![V[aX+b]=a^2V[X]+b^2V[1]](https://tex.z-dn.net/?f=V%5BaX%2Bb%5D%3Da%5E2V%5BX%5D%2Bb%5E2V%5B1%5D)
but the variance of a constant is 0. In this case, 
, so we're left with ![V[X+2]=V[X]](https://tex.z-dn.net/?f=V%5BX%2B2%5D%3DV%5BX%5D)
, as expected.
