Chapter 6.9, Problem 21STP

To determine

To find: Length, in kilometer of BB in the given figure.

Answer to Problem 21STP

Length of BB is 10 kilometers.

Explanation of Solution

Given information: 

Two similar triangles in which one is inside other (if join both shaded parts of it).

Concept used:

In similar triangles, the ratio of corresponding sides is equal always. So, in said given similar triangles,

  $\frac{\text{Hypotenues of outer triangle}}{\text{hypotenues of inner triangle}}=\frac{\text{Height of outer triangle}}{\text{Height of inner triangle}}$

Calculation:

Let, the length of BB be x , so based on above ratio set, on plug in all related value in it,

  $\frac{x}{5}=\frac{3+3}{3}$

On cross multiply,

  $x=\frac{6\times 5}{3}=2\times 5=10$

Based on above concept, the length of BB is 10 kilometers..