**AD is perpendicular to the side BC of an equilateral Δ ABC. Prove that 4AD² = 3AB².**

**Solution:**

**More Solutions:**

- If AD is extended to intersect BC at P, show that
- Show that AR > AQ.
- If O is any point in the interior of a triangle ABC.
- Construct a triangle ABC given that base BC = 5.5 cm.
- Which BC = 6.5 cm, ∠ B = 75° and ∠ A = 45°.
- Construct triangle ABC given that AB – AC = 2.4 cm.
- Prove that DBEF is a parallelogram.
- Prove that the four triangles.
- Prove that ∆DEF is also F, isosceles.
- If P is the mid-point of AD, prove that