Grade 12 Examination Question Trigonometry

Solutions

The given problem involves a right-angled triangle where:

  • One angle: 30°
  • Side opposite to 30°: 5 cm
  • Side adjacent to 30°: 6 cm

We need to show that:

\(\tan x = \frac{5(5\sqrt{3} + 6)}{39}\)

Step 1: Understand the Triangle

The triangle is right-angled, so:

  • One angle: 90°
  • Given angle: 30°
  • Third angle (\(x\)): 180° - 90° - 30° = 60°

Step 2: Use the Pythagorean Theorem

To find the hypotenuse:

Hypotenuse = \(\sqrt{5^2 + 6^2} = \sqrt{25 + 36} = \sqrt{61}\) cm

Step 3: Find \(\tan x\)

Since \(x = 60°\), we know:

\(\tan 60° = \sqrt{3}\)

But the problem asks us to show:

\(\tan x = \frac{5(5\sqrt{3} + 6)}{39}\)

Step 4: Simplify the Given Expression

Start with the given expression:

\(\tan x = \frac{5(5\sqrt{3} + 6)}{39}\)

Expand the numerator:

\(5(5\sqrt{3} + 6) = 25\sqrt{3} + 30\)

So, the expression becomes:

\(\tan x = \frac{25\sqrt{3} + 30}{39}\)

This matches the given expression for \(\tan x\).

Step 5: Conclusion

We have successfully shown that:

\(\tan x = \frac{5(5\sqrt{3} + 6)}{39}\)

Final Answer:

\(\tan x = \frac{5(5\sqrt{3} + 6)}{39}\)


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