The elementary profile of a dam is a representation of the cross-section of the dam and is used to determine the dimensions of the dam.

Right angled triangle profile is used in the construction of dams because it provides better stability and strength to the dam. The following are the reasons for choosing a right-angled triangle profile for a dam:

1. Stability: The right-angled triangle profile provides better stability to the dam because the weight of the water is distributed evenly over the base of the triangle. This helps to prevent the dam from toppling over due to the pressure of the water.

2. Strength: The right-angled triangle profile also provides better strength to the dam because the base of the triangle is wider than the top. This helps to distribute the weight of the water evenly and prevent the dam from collapsing due to the pressure of the water.

3. Cost-effective: The right-angled triangle profile is considered to be cost-effective because it requires less material to construct the dam compared to other profiles such as trapezoidal or rectangular profiles.

4. Easy to construct: The right-angled triangle profile is easy to construct because it requires less excavation work compared to other profiles. This helps to reduce the construction time and cost.

In conclusion, the right-angled triangle profile is the most suitable profile for the construction of dams due to its stability, strength, cost-effectiveness, and ease of construction.