Question

6. If 12a, 13a and 15a are the sides of a triangle then the area of the triangle is in sq. units)
(1) 20512²
(2) 20/142²
(3) 105142²
(4) 20/21a​

Answer 1

Step-by-step explanation:

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Answer 2

Given:

• 12a, 13a and 15a are the sides of a triangle.

To Find:

• Area of the triangle is in sq. units.

Solution:

We know the when three sides of a triangle are given Heroin's formula is used

Sides are a,b and c

                    $s = \frac{ a + b +c}{2}$

                  $Area= \sqrt{ s(s-a)(s-b)(s-c)}$

Putting the values

                 $s = \frac{12a + 13a +15a}{2}$

                 $s = 20a$

              $Area= \sqrt{ 20a(20a-12a)(20a-13a)(20a-15a)}$

           $Area= \sqrt{ 20a\times 8a \times 7a \times 5a}$

           $Area= 20 \sqrt{14} a^2$

Thus,  Area of the triangle is $20 \sqrt{14} a^2$  sq. units