Define what a net diagram of a 3D shape is and provide an example of how it represents the surface area.

A triangular prism has a base area of 30 square centimeters and a height of 10 centimeters. Calculate the volume of this triangular prism and then compare it to the volume of a triangular pyramid with the same base area and height.

[b] If \( b \) is the middle proportional between \( a \) and \( c \) , then prove that : \( \frac{a-b}{a-c}=\frac{b}{b+c} \)

the area of \( \triangle A B C=12 \mathrm{~cm}^{2} \), then \( \left(b^{2}+c^{2}-a^{2}\right) \tan A=\cdots \) 12 (b) 24

e) La somma e la differenza delle diagonali di un rombo misurano 126 cm e 18 cm . Calcola la misura del raggio della circonferenza inscritta nel rombo.

In the opposite figure : \( \frac{\mathrm{BE}}{\mathrm{BC}}= \) \( \begin{array}{ll}\text { (a) } \frac{1}{2} & \text { (b) } 2 \\ \text { (c) } \frac{1}{3} & \text { (d) } 3\end{array} \)