The equation \( C=2 \pi r \) is the formula that relates the circumference of a circle to the radius. This gives us the ability to calculate pi if we physically measure a circle's circumference and radius. Solve the equation for \( \pi \) to get the formula you would use to perform this activity. \( \pi=\frac{C}{3} \) \( \pi=2 r \) \( \pi=\frac{C}{2}-r \)

Problemi geometrici In un trapezio isoscele \( A B C D \) la base maggiore \( A B \) supera di 5 cm il doppio di \( B C \) e la base minore \( C D \) su- pera di 4 cm la lunghezza del lato obliquo \( B C \). Inoltre vale la relazione: \( \frac{1}{\overline{A B}+3}+\frac{1}{\overline{C D}}=\frac{5}{6 \overline{B C}} \) Determina perimetro e area del trapezio.

Find the slope of the line passing through the points \( (-8,9) \) and \( (-8,-6) \). slope: \( \square \) Find the slope of the line passing' through the points \( (-5,-4) \) and \( (3,-4) \). slope: \( \square \)

The movement of the progress bar may be uneven because questions can be worth more or les Simplify: \( \frac{-15\left(y^{2}\right)^{4}}{-5 y^{3} y^{2}} \)

3) \( \left\{\begin{array}{l}5 x+2 y=11 \\ 2 x-3 y=12\end{array}\right. \)

\( \star \) Divisibility Rules \( \cdot 2 \rightarrow \) last digit is even \( 2,4,6,8,10 \)