the perimeter of a triangle is 30 cm whose two sides are 4cm and 5 cm find the area
Answers
- No triangle is formed with sides 4 cm, 5 cm and perimeter as 30 cm.
Step-by-step explanation:
Given: We are given that perimeter of a triangle is 30 cm with sides 4 cm and 5 cm.
To find: We need to find the area of the triangle.
Solution:
Let us assume:
- First side = a = 4 cm
- Second side = b = 5 cm
- Third side = c = ?
We know that perimeter of a triangle is sum of all three sides of the triangle.
→ a+b+c = Perimeter
We know the values of a, b and perimeter. We are going to find the third side, which is c.
→ a+b+c = Perimeter
→ 4+5+c = 30
→ 9+c = 30
→ c = 30-9
→ c = 21 cm
Let us find the semi-perimeter of the triangle.
→ Semi perimeter = Perimeter/2
→ Semi perimeter = 30/2
→ Semi perimeter = 15 cm
Now, we are going to use Heron's formula to find the area of triangle. By applying the formula, we get:
→ Area = √s(s-a)(s-b)(s-c)
→ Area = √15(15-4)(15-5)(15-21)
→ Area = √15(11)(10)(-6)
→ Area = √15(11)(10)(-6)
→ Area = √-9900
We know that, the number inside the square root cannot be negative or less than 0. Hence, we can say that:
No triangle is formed with sides 4 cm, 5 cm and perimeter as 30 cm.