# Math Help - absolute value with sinθ

1. ## absolute value with sinθ

I encountered an question of calculation of volume.
The following is a part of the solution.
I don't know why the highlighted sinθ has an absolute value sign.
Can anyone explain to me? Thank you.

2. ## Re: absolute value with sinθ

Because $\sqrt{a^2}= |a|$, not a.

For example, $\sqrt{(-2)^2}= \sqrt{4}= 2$, not $-2$.

3. ## Re: absolute value with sinθ

Thank you, HallsofIvy.