In the adjoining figure, $\triangle CAB$ is a right triangle, right angled at A and $AD \perp BC$. Prove that $\triangle ADB \sim \triangle CDA$. Further, if $BC = 10$ cm and $CD = 2$ cm, find the length of AD. 
In the diagram, the lines QR and ST are parallel to each other. The shortest distance between these two lines is half the shortest distance between the point P and the line QR. What is the ratio of the area of the triangle PST to the area of the trapezium SQRT?
Note: The figure shown is representative

\( AB \) is a diameter of the circle. Compare:
Quantity A: The length of \( AB \)
Quantity B: The average (arithmetic mean) of the lengths of \( AC \) and \( AD \). 
O is the center of the circle above. 
Two soils of permeabilities \( k_1 \) and \( k_2 \) are placed in a horizontal flow apparatus, as shown in the figure. For Soil 1, \( L_1 = 50 \, {cm} \), and \( k_1 = 0.055 \, {cm/s} \); for Soil 2, \( L_2 = 30 \, {cm} \), and \( k_2 = 0.035 \, {cm/s} \). The cross-sectional area of the horizontal pipe is 100 cm², and the head difference (\( \Delta h \)) is 150 cm. The discharge (in cm³/s) through the soils is ........ (rounded off to 2 decimal places).

The most suitable test for measuring the permeability of clayey soils in the laboratory is ___________.
Consider the beam ACDEB given in the figure. Which of the following statements is/are correct:

The figures, I, II, and III are parts of a sequence. Which one of the following options comes next in the sequence as IV?
