Answer:
56 trees will make 10000 newspapers.
Step-by-step explanation:
Given:
One tree makes approximately 230 newspapers.
Now, for estimating how many newspapers will be made with 56 trees.
By multiplying 
trees with 
newspapers we get,
.
And, rounding 
to one significant number (1 S.F.) is 
.
Therefore, 56 trees will make 10000 newspapers.
Answer:
50 cups of coffee
Step-by-step explanation:
So what you do is take 3.50 then subtract 1.50 to get the profit of one cup of coffee. ($2) Then you do the $100 and divide it by the $2 and find out how many cups of coffee he has to sell to get to the $100. (50)
25 sq rt of 3 = 43.3
30 degrees = X 60 = X sq rt of 3. 90 degrees = 2x
Simplification = 3.5x + 2.5x
Result = 6x
OK, so the graph is a parabola, with points x=0,y=0; x=6,y=-9; and x=12,y=0
Because the roots of the equation are 0 and 12, we know the formula is therefore of the form
y = ax(x - 12), for some a
So put in x = 6
-9 = 6a(-6)
9 = 36a
a = 1/4
So the parabola has a curve y = x(x-12) / 4, which can also be written y = 0.25x² - 3x
The gradient of this is dy/dx = 0.5x - 3
The key property of a parabolic dish is that it focuses radio waves travelling parallel to the y axis to a single point. So we should arrive at the same focal point no matter what point we chose to look at. So we can pick any point we like - e.g. the point x = 4, y = -8
Gradient of the parabolic mirror at x = 4 is -1
So the gradient of the normal to the mirror at x = 4 is therefore 1.
Radio waves initially travelling vertically downwards are reflected about the normal - which has a gradient of 1, so they're reflected so that they are travelling horizontally. So they arrive parallel to the y axis, and leave parallel to the x axis.
So the focal point is at y = -8, i.e. 1 metre above the back of the dish.
