Multiple choice

The angle of depression of two post $P$ and $Q$ at a distance of $2$ meter on the same side of a road from a balloon $(B)$ vertically over the road are observed to be $\displaystyle 45^{\circ}$ and $\displaystyle 60^{\circ}$. What is the height of the balloon?

  1. $\displaystyle 3 -\sqrt{3}$
  2. $\displaystyle \sqrt{3}-1$
  3. $\displaystyle 3+\sqrt{3}$
  4. $\displaystyle \sqrt{3}+1$
Reveal answer Fill a bubble to check yourself
C Correct answer
AI explanation

Let h be the height of the balloon and d be its horizontal distance from the closer post. Using the 60 degree angle of elevation at the closer post, tan(60) = h divided by d, so d equals h divided by sqrt(3). At the farther post, which is 2 m further away, tan(45) = h divided by (d + 2). Substituting d gives 1 = h divided by ((h divided by sqrt(3)) + 2). Solving this equation yields h = 3 + sqrt(3).