Explanation

Trapezoidal drains handle large water flows efficiently in heavy rainfall.

They are stable and easy to construct on hilly slopes.

Explanation

A hipped roof slopes downward on all four sides toward the walls.

Provides better stability and resistance to wind compared to gable roofs.

Explanation

The sill is the horizontal bottom frame of a door or window.

It supports the door/window and provides a level base for installation.

Explanation

In a circular pipe, flow velocity is maximum at the center and zero at the pipe walls due to friction.

This follows the parabolic velocity profile of laminar flow.

Explanation

Voussoirs are wedge-shaped bricks or stones used to construct an arch.

They help distribute compressive forces along the curve of the arch.

Explanation

Cavity walls have a gap between two layers to prevent moisture penetration.

Commonly used in damp-prone areas to protect interiors from water seepage.

Explanation

An equilateral triangle has all three sides and angles equal (each angle = 60°).

It is commonly used in geometry and structural design for uniform load distribution.

A scalene triangle has no equal sides and no equal angles.

All sides and angles are of different lengths and measures.

Explanation

A frog is the shallow depression on one face of a brick.

It reduces brick weight and provides a key for mortar to bond.

Explanation

English bond alternates headers and stretchers in each course, providing maximum strength.

Commonly used in load-bearing walls due to its durability and stability.

Explanation

Dewatering is the process of removing water from foundations, pits, or trenches.

It ensures a dry work area and prevents soil instability during construction.