27
You can find the area of a triangle with base b and height h using this formula.
A=
1
2
bh
The triangle has base b=6miles and height h=9miles.
Find the area.
A
=
1
2
bh
=
1
2
(6)(9)
= (3)(9)
= 27
The area of the triangle is 27 square miles.
Composing functions just means to feed the ouput of the inner one as the input for the outer one.
So, the following writings are equivalent:

Using the second form, we can see that the first thing to do is to compute
, which is given:

This means that we can update the fomula:

So, now we have to compute
. Given
, we know that
doubles the input and adds one. In this case, the input is
, so we have to double this and add one:

So, we have

Similarly, from
, we understand that
just adds 3 to the input. In this case, the input is
, so we'll add 3 to this quantity:

So, we finally have

So, we write a fraction, which would be 12/100. Then we would do 12/100 = x/550. You could divide 100 by 550, which is 5.5. Then we would multiply 5.5 by 12, which is 66. So 66 people would be wearing glasses.
Answer:
look at the picture I sent
Plot 6 directly above 6. Plot root83 between 9 and 10 but nearer to 9 since its value in 3 significant figures is 9.11,
Plot root40 between 6 and 7 but nearer to 6 since its value in 3 significant figures is 6.32,
Plot root64 directly above 8 since 8x8=64,
And lastly plot 7.5 just in between 7 and 8,
Hope this helps ;)