(a) From the pyramid, construct \(\Delta BFG\) by drawing a line from B to F.

\(|BF|^{2} = 4^{2} + 3^{2}\)
\(|BF| = 25 \implies |BF| = 5m\)
In calculating the height,
\(h^{2} = 5^{2} - (\frac{5}{2})^{2}\)
\(h^{2} = \frac{75}{4}\)
\(h = \sqrt{75}{4}\)
= \(4.33 m\)
Volume of a pyramid = \(\frac{1}{3} \times 4 \times 3 \times 4.33\)
= \(17.32 m^{3}\)
Volume of a cuboid = \(l \times b \times h\)
= \(3 \times 4 \times 2\)
= \(24 m^{3}\)
Total volume of the shape = \(17.32 + 24\)
= \(41.32 m^{3}\)
(b) \(5 - (x - 2) = d\)
\((x + 2) - 5 = d\)
\(\therefore (x + 2) - 5 = 5 - (x - 2)\)
\(x - 3 = 7 - x\)
\(2x = 10\)
\(x = 5\)