Chapter 6: Problem 30
Find the area of the triangle whose sides have the given lengths. \(a=11, \quad b=100, \quad c=101\)
Short Answer
Expert verified
The area of the triangle is approximately 174 square units.
Step by step solution
01
Determine if a triangle is valid
To verify if the given sides can form a triangle, check the triangle inequality: the sum of the lengths of any two sides must be greater than the length of the third side. Here are the checks: 1. \(a + b > c\) which is \(11 + 100 > 101\) or \(111 > 101\), which is true. 2. \(a + c > b\) which is \(11 + 101 > 100\) or \(112 > 100\), which is true. 3. \(b + c > a\) which is \(100 + 101 > 11\) or \(201 > 11\), which is true. Thus, the sides can form a triangle.
02
Calculate the semi-perimeter
The semi-perimeter \(s\) of a triangle with sides \(a\), \(b\), and \(c\) is calculated using the formula: \[ s = \frac{a + b + c}{2} \] Substitute the given values: \[ s = \frac{11 + 100 + 101}{2} = \frac{212}{2} = 106 \]
03
Use Heron's Formula for area
Heron's formula for the area \(A\) of a triangle with sides \(a\), \(b\), and \(c\) and semi-perimeter \(s\) is: \[ A = \sqrt{s(s-a)(s-b)(s-c)} \] Substitute the known values: \[ A = \sqrt{106(106-11)(106-100)(106-101)} \] Simplify the expressions: \[ A = \sqrt{106 \times 95 \times 6 \times 5} \]
04
Simplify and calculate
Calculate the expression inside the square root: \[ 106 \times 95 \times 6 \times 5 = 30270 \] Find the square root of the result to get the area: \[ A = \sqrt{30270} \approx 174 \] Thus, the area of the triangle is approximately 174 square units.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Heron's formula
Heron's formula is a convenient way to find the area of a triangle when you know the lengths of all three sides and do not have the height readily available. It is especially handy for non-right triangles.
Before using Heron's formula, make sure the sides can form a valid triangle, which can be confirmed using the triangle inequality theorem.
This formula is:
In our example, substitute the values for a = 11, b = 100, and c = 101 to find the area using the semi-perimeter s calculated earlier.
Before using Heron's formula, make sure the sides can form a valid triangle, which can be confirmed using the triangle inequality theorem.
This formula is:
- Compute the semi-perimeter, denoted as s.
- Use the formula: \[A = \sqrt{s(s-a)(s-b)(s-c)}\]
In our example, substitute the values for a = 11, b = 100, and c = 101 to find the area using the semi-perimeter s calculated earlier.
triangle inequality theorem
Before attempting to calculate the area with Heron's formula, it's crucial to check if the sides can indeed form a triangle. This is where the triangle inequality theorem comes into play. It helps determine if any three given lengths can be sides of a triangle.
The principle states:
The principle states:
- The sum of the lengths of any two sides must be greater than the length of the remaining side.
- You need to check all three combinations:
- \(a + b > c\)
- \(a + c > b\)
- \(b + c > a\)
semi-perimeter calculation
Once you've established that a valid triangle can be formed, the next step in using Heron's formula is calculating the semi-perimeter of the triangle.
The semi-perimeter is essentially half of the triangle's perimeter and is crucial in calculating area with Heron's formula.
Calculate it using the formula:
The semi-perimeter is essentially half of the triangle's perimeter and is crucial in calculating area with Heron's formula.
Calculate it using the formula:
- \[s = \frac{a + b + c}{2}\]
- Where a, b, c are the lengths of the sides.
- Add the side lengths: \(11 + 100 + 101 = 212\)
- Divide by 2:\(s = \frac{212}{2} = 106\)