If a triangle has sides 4cm,7cm and 9cm long, what is its area? (no answers pls want the working)
Here's the formula.
http://www.mathgoodies.com/lessons/vol1/area_triangle.html
Answer questions
Well, let's get this party started and calculate the area of this triangle! We can use Heron's formula, which states that the area of a triangle with sides a, b, and c is given by:
Area = √(s(s-a)(s-b)(s-c))
where s is the semiperimeter of the triangle, calculated as:
s = (a + b + c) / 2
Now, in our case, the sides are 4cm, 7cm, and 9cm. So, let's find the semiperimeter first:
s = (4 + 7 + 9) / 2 = 20 / 2 = 10 cm
Now let's substitute the values into Heron's formula:
Area = √(10(10-4)(10-7)(10-9))
Area = √(10 * 6 * 3 * 1)
Area = √(180)
And the secret answer is...
Area ≈ 13.42 cm² (rounded to two decimal places)
So, there you have it! The area of the triangle is approximately 13.42 cm². Ta-dah!
To find the area of a triangle, we can use Heron's formula. Heron's formula states that the area of a triangle can be found using the lengths of its sides, let's call them a, b, and c.
The formula is as follows:
Area = sqrt(s(s-a)(s-b)(s-c))
Where s is the semi-perimeter of the triangle, given by:
s = (a + b + c) / 2
In this case, the lengths of the sides are given as 4 cm, 7 cm, and 9 cm.
Let's now calculate the semi-perimeter of the triangle using the formula:
s = (4 + 7 + 9) / 2 = 20 / 2 = 10 cm
Now, we can calculate the area of the triangle using Heron's formula:
Area = sqrt(10(10 - 4)(10 - 7)(10 - 9))
Let's evaluate the expression step-by-step.
1. 10 - 4 = 6
2. 10 - 7 = 3
3. 10 - 9 = 1
4. Multiply the four values: 10 * 6 * 3 * 1 = 180
Now, let's find the square root of 180:
Area = sqrt(180)
Calculating the square root of 180, we find that:
Area ≈ 13.416 cm²
Therefore, the approximate area of the triangle is 13.416 cm².
To find the area of a triangle, you can use Heron's formula. Heron's formula states that the area (A) of a triangle with side lengths of a, b, and c can be calculated as:
A = sqrt(s(s-a)(s-b)(s-c))
where s is the semi-perimeter of the triangle, calculated as:
s = (a + b + c)/2
In this case, the side lengths of the triangle are given as 4cm, 7cm, and 9cm. To calculate the area, we need to find the semi-perimeter (s) first.
s = (4 + 7 + 9)/2
s = 20/2
s = 10cm
Now, we can substitute the values of the side lengths and the semi-perimeter into Heron's formula to find the area (A).
A = sqrt(10(10-4)(10-7)(10-9))
Now, let's calculate each term:
A = sqrt(10(6)(3)(1))
A = sqrt(180)
A = 13.42 square cm (rounded to two decimal places)
Therefore, the area of the triangle with side lengths 4cm, 7cm, and 9cm is approximately 13.42 square cm.