Not so sure about the second one, but the first one is pretty simple:
The area of a circle = pi x radius^2
Since you need to find the area of the entire dvd, I'm assuming they mean if the hole in the center wasn't there, so add that to the diameter.
12+1.5 = 13.5
Half of the diameter is the radius, so half of 13.5 = 6.75
Now, multiply pi (3.14) by the radius, but have the radius squared. You'd write the equation like this:
3.14 x 6.75^2 (or on paper, the ^2 would be a small two diagonal from the 5)
Actual answer: 143.06625
You can round that to 143.
35 = 1/2h (6+1)
35 = 1/2 h + 7
28 = 1/2h
14 = 1h
14 = h
Let the year represents x axis and consumption represents y axis.
Since 2010 is the initial year, x=0
and 2013 is third year , so x=3
Co-ordinates are (0,8.938)(3,10.480)
Exponential formula is 
Putting the value of x in the above formula from 1st coordinate,
As 
= 1
this gives a= 8.938
Now using the 2nd coordinate
putting the value of a in it we have
taking cube roots on both sides we get
b= 1.05448
Now putting the values of a and b in the exponential formula-
In the year 2028, x=28
so,
y= 39.474
Hence oil consumption per day in 2028 will be 39.474 million barrels.
Answer:
640.5 cm^2
Step-by-step explanation:
So the formula for trapezoid is height times the average of the bases. So 25+36=61, and then we divide that by 2 to get 30.5 as our average. Then, we take 30.5 and multiply it by 21 and we get 640.5.
