# ABC is a triangle in which altitudes BE and CF to sides AC and AB are equal (see Fig. 7.32). Show that

(i) ΔABE ≅ ΔACF

(ii) AB = AC, i.e., ABC is an isosceles triangle.

**Solution:**

**(i)** In ΔABE and ΔACF,

∠AEB = ∠AFC (Each 90°)

∠A = ∠A (Common angle)

BE = CF (Given)

∴ ΔABE ≅ ΔACF (By AAS congruence rule)

**(ii)** We have proved above that ΔABE ≅ ΔACF

∴ AB = AC (By CPCT)

Hence, ΔABC is an isosceles triangle.

**Video Solution:**

## ABC is a triangle in which altitudes BE and CF to sides AC and AB are equal (see Fig. 7.32). Show that (i) ΔABE ≅ ΔACF (ii) AB = AC, i.e., ABC is an isosceles triangle.

### NCERT Maths Solutions Class 9 - Chapter 7 Exercise 7.2 Question 4:

**Summary:**

If ABC is a triangle in which altitudes BE and CF to sides AC and AB are equal, then ΔABE ≅ ΔACF using AAS congruency and AB = AC i.e., ABC is an isosceles triangle.