Question

in triangle ABC, AB=15cm BC =14 cm AC =13 cm find the area of triangle ABC​

Answer 1

Answer:

In ∆ABC, AB = 15 cm , BC = 13 cm and AC = 14 cm.

By Heron's formula ,

S = ( A + B + C ) / 2

S = ( 15 + 13 + 14 ) / 2

S = 42 / 2

S = 21

Now, area of triangle

= √S (S–A) (S–B) (S–C)

= √21 (21–15) (21–13) (21–14)

= √21 (6) (8) (7)

= √7056

= 84 cm2

Again,area of triangle = 1/2×base×altitude=84 cm2

1/2×14×altitude = 84

7 × altitude=84

altitude = 84/7

Altitude = 12cm

Therefore, the area of ∆ABC is 84cm² and its altitude on AC is 12 cm.

Step-by-step explanation:

hope it helps you

Answer 2

Answer:

Step-by-step explanation:

Use the Heron's formula for calculating the Area of the triangle when length of 3 sides are known.

a = 15 cm, b = 14 cm, c = 13 cm.

s = a + b + c/2 = 15 + 14+ 13/2 = 42/2 = 21

Area of triangle = √s(s-a)(s-b)(s-c)

                          = √21(21-15)(21-14)(21-13)

                          =√21*6*7*8

                          =√7056

                          = 84 cm².