Question

find the area of a triangle two sides of which are 18cm and 10cm and perimeter 42 cm

Answer 1

Given sides
a = 18
b = 10
_______________
Perimeter = a+b+c
42 = 18+10+c
c = 14
_______________
S = (a+b+c)/2
= 21
=================
Using Heron's formula Area of triangle is
= root (s)×(s-a)×(s-b)×(s-c)
= root (21)×(21-18)×(21-10)×(21-14)
= root (21×3×11×7)
= root (21×21×11)

Area = 21√11 units
_________________

Answer 2

Question:

• Find the area of a triangle two sides of which are 18cm and 10cm and perimeter 42 cm.

Answer:

• Therefore, the area of the triangle is 21√11 cm².

Step-by-Step Explanation:

Given:

• Two sides of the ∆ are 18 cm and 10 cm & the perimeter is 42 cm.

To find:

• Area of the triangle

Solution:

Let's Consider, the third side be x cm.

★ Perimeter of ∆ = (a + b + c)

➟ 18 + 10 + x = 42

➟ 28 + x = 42

➟ x = 42 – 28

➟ x = 14

• The third side of the triangle is 14 cm.

If the perimeter of the triangle is 42 cm then semi perimeter of the triangle would be 21 cm. i.e ( s ) = 21 cm.

Using Heron's Formula :

➟ ⠀Ar. = √(s – a) (s – b) (s – c)

➟ ⠀Ar. = √(21 – 18) (21 – 10) (21 – 14)

➟ ⠀Ar. = √7 × 3 × 3 × 11 × 7

➟ ⠀Ar. = 7 × 3√11

➟ ⠀Ar. = 21√11

Therefore, the area of the triangle is 21√11 cm².

_____________________________

нσρє iт нєℓρѕ

нαρρу ℓєαяηiηg :)

тнαηк үσυ

||TheUnkownStar||