Find the size of h and g in the diagram below.

The length ($L$) is $104 \text{ m}$ and the breadth ($B$) is $76 \text{ m}$. The diagonal ($D$) can be found using the Pythagorean theorem:

The distance from the centre spot to a corner is half the length of the diagonal.

The distance from the centre spot to a corner is approximately $\boxed{\text{64.41 m}}$.

2. School compound plan

Assumption: The scale "2cm:10cm" is likely a typo and should be "2cm:10m" for a school compound plan. We will proceed with the assumption that $2 \text{ cm}$ on the drawing represents $10 \text{ m}$ in reality. This simplifies to a scale of $1 \text{ cm} : 5 \text{ m}$.

The actual length is $160 \text{ m}$ and the actual breadth is $106 \text{ m}$.
The scale is $1 \text{ cm}$ on the drawing for every $5 \text{ m}$ in reality.

The length on the drawing is $\boxed{\text{32 cm}}$ and the breadth on the drawing is $\boxed{\text{21.2 cm}}$.

3. Triangle

The diagram shows a triangle with two sides marked with single dashes, indicating that these sides are equal in length. This means it is an isosceles triangle. In an isosceles triangle, the angles opposite the equal sides are equal. One base angle is given as $63^\circ$. Therefore, the other base angle, $g$, must also be $63^\circ$.

The sum of angles in any triangle is $180^\circ$. So, we have:

Substitute the value of $g$:

The size of $g$ is $\boxed{63^\circ}$ and the size of $h$ is $\boxed{54^\circ}$.