**Important Concepts and Formulas**

1.

**Division of a line segment:**Suppose a line segment is given and you have to divide it in a ratio, say 2 : 3. You may do it by measuring the length and then marking a point on it that divides it in the given ratio. But suppose you do not have any way of measuring it precisely, then you can divide the given line segment by the section method.
2. We can construct a triangle similar
to a given triangle as per given scale factor.

3. We can construct the pair of tangents
from an external point to a circle.