kitty<3

It is . . . currently around 75 degrees outside.

But seriously, if you want a specific answer, please make your question more specific, such as posting the picture of the triangle with the angle in question. Since a triangle has 180 degrees total for its three angles, an angle A could be anywhere from 1  to 178 degrees.

Lateral surface area is the surface area of an object, excluding the area of the base(s).

So the formula for the lateral surface area of a cylinder would be: $${\mathtt{A}} = {\mathtt{2}}{\mathtt{\,\times\,}}{\mathtt{\pi}}{\mathtt{\,\times\,}}{\mathtt{r}}{\mathtt{\,\times\,}}{\mathtt{h}}$$ where r is radius of the circular base and h is the height.

Start by substituting in the values for r and h. And for this problem, pi will be the approximate value of 3.14

$${\mathtt{A}} = {\mathtt{2}}{\mathtt{\,\times\,}}{\mathtt{3.14}}{\mathtt{\,\times\,}}{\mathtt{9.6}}{\mathtt{\,\times\,}}{\mathtt{7}} \Rightarrow {\mathtt{A}} = {\mathtt{422.016}}$$

The lateral S.A. of the cylinder would be  about 422 meters².

Another way would be to think of the lateral surface area of the cylinder as the circumference of the base circle, multiplied by the height of the cylinder.

A cylinder is like stacking a bunch of circles together, so the surface area of the cylinder would be the circumferences of all the circles added together. Adding the circumferences together multiple times would be equivalent to multiplying them by the height of the cylinder.

So another way to find the lateral surface area of a cylinder would be:

$${\mathtt{A}} = {\mathtt{C}}{\mathtt{\,\times\,}}{\mathtt{h}}$$ where C is the circumference of the base and h is the height:)

For this question, you can use the Pythagorean Theorem: $${{\mathtt{a}}}^{{\mathtt{2}}}{\mathtt{\,\small\textbf+\,}}{{\mathtt{b}}}^{{\mathtt{2}}} = {{\mathtt{c}}}^{{\mathtt{2}}}$$ since this is a right triangle. A and b are the legs (shorter sides) of the triangle and c is the hypotenuse (longest side, diagonal side).

a  and b are 8 and 5 since the length of the wire is the diagonal side of the right triangle. So set up the equation:

$${{\mathtt{8}}}^{{\mathtt{2}}}{\mathtt{\,\small\textbf+\,}}{{\mathtt{5}}}^{{\mathtt{2}}} = {{\mathtt{c}}}^{{\mathtt{2}}}$$

Simplify the left side:

64 + 25 = c²

89 = c²

Now take the square root of both sides:

$${\sqrt{{\mathtt{89}}}} = {\mathtt{9.433\: \!981\: \!132\: \!056\: \!603\: \!8}}$$ = c

So the wire is about 9.434 or 9.4 feet long.

If you mean finding the cosine of a specific angle, use the cosine button. Starting from the left, it is in the first column.The cos( ) button is in the third row down.

It works for angles in both radians and degrees, but you will need to select radians if you are using that, since the calculator defaults to degrees.

You can also directly type in cos(   ) to the calculator:)

For #7 - 13, it is mostly using the Distributive Property, as well as polynomial multiplication.

The formula for the volume of a pyramid is:

$${\mathtt{V}} = {\frac{{\mathtt{1}}}{{\mathtt{3}}}}{\mathtt{\,\times\,}}{\mathtt{Ah}}$$ where A is the area of the base and h is the height of the pyramid (perpendicular to the base, not the slant height).

The area of the base for a triangular pyramid would be the area of the triangle, which would be $${\frac{{\mathtt{1}}}{{\mathtt{2}}}}{\mathtt{\,\times\,}}{\mathtt{Bh}}$$ where b is the length of the base of the triangle, and h is the height of the triangle.

Once you find the area of the pyramid's base, substitute that value for A in the first equation above, and multiply it by (1/3) and the height of the pyramid.

This page can help as well:

http://www.mathsteacher.com.au/year10/ch14_measurement/25_pyramid/21pyramid.htm

That would, I believe, depend on what A is.

Fibonacci.

http://www.maths.surrey.ac.uk/hosted-sites/R.Knott/Fibonacci/fibBio.html

It's what happens... when you

That's great, CPhill! :D

I just found another way by working backwards:

22/2 = 11, and 3*4 = 12, minus 1 = 11

So 22 = $$\left(\left({\mathtt{3}}{\mathtt{\,\times\,}}{\mathtt{4}}\right){\mathtt{\,-\,}}{\mathtt{1}}\right){\mathtt{\,\times\,}}{\mathtt{2}} = {\mathtt{22}}$$