Typo in math level 2 sparknotes?

Archive SAT Subject Test Preparation
1

<p>It says that the lateral surface area of a cone = pi<em>r</em>l
Then it says that the alternative is 1/2<em>pi</em>c*l (is the circumference and l is the lateral height)</p>

<p>Is the second formula right? How can 1/2*c=r? What’s the correct alternative of the first formula?</p>

2

<p>r = c/(2pi)
pi<em>r</em>l = 1/2<em>c</em>l</p>

3

<p>^Thanks. The equations make much more sense.</p>

4

<p>You are welcome!
Unfortunately, there are few more typos in SN Math (I don’t have a list) - not as many as in some other test prep books.</p>