Question

Find the missing length indicated
A) 25
B) 5
C) 8
D) 3

Answer 1

Given:

The figure of a triangle.

To find:

The missing length.

Solution:

Let x be the missing length.

Basic proportionality theorem(BPT): According to this theorem, if a line is parallel to the one side of a triangle then that the line intersects the other two sides of the triangle in the same ratio.

Using Basic proportionality theorem, we get

$\dfrac{6}{8-6}=\dfrac{12-x}{x}$

$\dfrac{6}{2}=\dfrac{12-x}{x}$

$3=\dfrac{12-x}{x}$

$3x=12-x$

Adding x on both sides, we get

$3x+x=12$

$4x=12$

$x=\dfrac{12}{4}$

$x=3$

The missing length is 3 Therefore, the correct option is D.