Answer:
78
Step-by-step explanation:
You take the original total: 60, and multiply it by 30 to get 1,800. You then divide 1,800 by 100 to get 18. 18 is your 30%. Now, you add the 30% to 60 getting your total number of ducks: 78.
The equation version:

It is just proportions.
Answer:
x^2 - 2x + 5 = 0.
Step-by-step explanation:
The (0, 5) is the point where the parabola passes through the y axis (where x = 0), so we can write the equation as
y = ax^2 + bx + 5 where a and b are constants to be found.
Also, since (1, 4) and (2, 5) are points on the curve, substituting, we have the system:
a(1)^2 + 1b + 5 = 4
a(2)^2 + 2b + 5 = 5
Simplify these 2 equations:
a + b = -1 .................(1)
4a + 2b = 0..................(2)
Multiply the first equation by -2:
-2a - 2b = 2 .................(3)
Add (2) + (3):
2a = 2
a = 1.
Substitute a = 1 into (2):-
4*1 + 2b = 0
2b = -4
b = -2.
Answer:
Step-by-step explanation:
Rising 30 feet for every 400 feet of track is not a very large angle of elevation. We set this up as a right triangle to use right triangle trig to solve for the missing angle. The height is 30 and the hypotenuse is 400. The height is the side opposite the angle in question, and the hypotenuse is the hypotenuse! This is the sin ratio. Setting up the ratio using our info:

When you are looking for a missing angle measure, as we are here, use the 2nd-->sin buttons to find the inverse of sin, which looks like this:

Enter in the fraction 30/400 after the parenthesis and then hit enter to get the angle measure of 4.3 degrees.