Krishna
0

Step 1: Examine the given figure and make a note of the given measurements

Step 2: Prove that the two triangles are similar by using the given data.

EXPLANATION: From the figure we get

\angle B = \angle D = 90 \degree

\angle BCA = \angle DCE

Because, angle of incidence and angle of reflection are same)

So, ∆ABC ~ ∆EDC ( by AAA Theorem)

Step 3: Use the AAA theorem to calculate unknown value

AAA THEOREM: In two triangles, if the angles are equal, then the sides

opposite to the equal angles are in the same ratio (or proportional) and hence

the two triangles are similar.

\frac{AB}{ED}=\frac{BC}{CD}

Step 4: Substitute the known values in the AAA theorem

EXAMPLE:  \frac{1.5}{h}=\frac{0.4}{87.6}

h=\frac{1.5*87.6}{0.4}

h = 328.5 m

The height of the lamp post is 328.5 m