First, figure out what you do and don't know....
You do know that 3 times the sum of a number and 4 is 18 more than the number....you don't know the number so you make it the variable x
now take 3 times the sum of a number and 4 and make that an expression 3x+4 this expression is the same or equal to the sum of x and 18 x+18
3x+4=x+18
2x+4=18
2x=14
x=7
hope this helped :)
V = a²h/3
Plugging values in we get 8.67X10^7, or 86,700,000
Answer:
- The measure of reference angle is
. 
Step-by-step explanation:
Converting 
to degrees,
This means lies in Quadrant 4, and thus its reference angle is 
Since lies in the fourth quadrant, 
and 
are negative.
Since lies in the fourth quadrant, 
is positive, and is equal to 
Answer:
612 Hz.
Step-by-step explanation:
The frequency of the sound will be proportionally higher when coming towards you. The increase is related to the speed of the train.
So the frequency will be:
580 + (580 / 343) * 18.8
= 612 Hz.
This is called the Doppler effect.
