What is the difference between 1.8 and 1.08?

Answer

4

Explanation

AP is a tangent meeting a secant BP at P outside the circle.  

(PA)² = (PE)(PB)

PA = 6 and chord BE= 5.

Let PE = x

6² = x(x+5)

36 = x² + 5x

x² + 5x + 2.5² = 36 + 2.5²

(x + 2.5)² = 42.25

(x + 2.5) = √ 42.25 = 6.5

x = 6.5 - 2.5 = 4         or  x = -6.5 - 2.5  = -9

But since length cannot be negative, x = 4.