Find the area of triangle ABC if its perimeter is 35cm².
AB: 10cm²
BC: 10cm ²
AC: 15cm ²
Find area by heron's formula.
{ √s(s-a) (s-b) (s-c) }
Answers
Answer:
The area of triangle ABC is 49.69 cm².
Step-by-step-explanation:
We have given that,
For △ABC,
- AB ( a ) = 10 cm
- BC ( b ) = 10 cm
- AC ( c ) = 15 cm
- P ( △ABC ) = 35 cm
We have to find the area of the triangle.
Now,
Semi perimeter ( s ) = Perimeter / 2
⇒ s = P ( △ABC ) / 2
⇒ s = 35 / 2
⇒ s = 17.5 cm
Now, by Heron's formula,
Area of triangle = √[ s ( s - a ) ( s - b ) ( s - c ) ]
⇒ Area of triangle = √[ 17.5 ( 17.5 - 10 ) * ( 17.5 - 10 ) * ( 17.5 - 15 ) ]
⇒ Area of triangle = √[ 17.5 * 7.5 * 7.5 * 2.5 ]
⇒ Area of triangle = 7.5 √( 17.5 * 2.5 )
⇒ Area of triangle = 7.5 √( 2.5 * 7 * 2.5 )
⇒ Area of triangle = 7.5 * 2.5 √7
⇒ Area of triangle = 7.5 * 2.5 * 2.645
⇒ Area of triangle = 7.5 * 2.5 * 2.65
⇒ Area of triangle = 2.5 * 3 * 2.5 * 2.5 * 1.06
⇒ Area of triangle = 6.25 * 3.18 * 2.5
⇒ Area of triangle = 6.25 * 7.95
⇒ Area of triangle = 49.6875
⇒ Area of triangle ≈ 49.69
∴ The area of triangle ABC is 49.69 cm².
Information provided with us:
- Perimeter of a triangle ABC is 35 cm²
- Length of AB = 10 cm²
- Length of BC = 10 cm²
- Length of AC = 15 cm²
What we have to calculate:
- We have to calculate the area of that triangle by using heron's formula
Performing Calculations:
- In order to calculate the area of that triangle we need to first find out the semi perimeter of that triangle.
Formula of semi-perimeter:-
- Semi perimeter = a + b + c / 2
We have,
- a is 10
- b is 10
- c is 15
Substituting the values,
➺ Semi perimeter = 10 + 10 + 15 / 2
➺ Semi perimeter = 20 + 15 / 2
➺ Semi perimeter = 35 / 2
➺ Semi perimeter = 17.5
Finding out the area of triangle by using heron's formula:
- [ √s(s-a) (s-b) (s-c) ]
As we got,
- s is 17.5 cm
Substituting the values of a , b, c and s,
➺ Area = √[17.5 (17.5 - 10) (17.5 - 10) (17.5 - 15)]
➺ Area = √[17.5 (7.5) (7.5) (2.5)
➺ Area = √[17.5 × 7.5 × 7.5 × 2.5]
➺ Area = √[131.25 × 7.5 × 2.5]
➺ Area = √[131.25 × 18.75]
➺ Area = √[2460. 93]
➺ Area = 49.68 (Approx)
- Henceforth, area of triangle by using heron's formula is 49.68cm
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