Solving for the Missing Leg

Oct 13, 2025 by wbrum.org 84 views

Introduction

The Pythagorean theorem is a fundamental concept in geometry that describes the relationship between the lengths of the sides of a right triangle. It states that the square of the length of the hypotenuse (the side opposite the right angle) is equal to the sum of the squares of the lengths of the other two sides. In this article, we will use the Pythagorean theorem to solve for the length of the missing leg in a right triangle.

The Pythagorean Theorem

The Pythagorean theorem is given by the equation:

a^2 + b^2 = c^2

where a and b are the lengths of the legs of the right triangle, and c is the length of the hypotenuse.

Given Equation

We are given the equation:

a^2 + 16^2 = 20^2

where a is the length of the missing leg, and 16 and 20 are the lengths of the other two sides.

Step 1: Evaluate Powers

The first step is to evaluate the powers on the left-hand side of the equation:

a^2 + 256 = 400

This simplifies the equation by removing the exponent.

Step 2: Undo Addition

The next step is to undo the addition on the left-hand side of the equation:

a^2 = 144

This isolates the term with the variable a.

Step 3: Undo the Square

The final step is to undo the square on the left-hand side of the equation:

a = √144

This gives us the value of the missing leg.

Solving for the Missing Leg

Now that we have simplified the equation, we can solve for the missing leg. We have:

a = √144

To find the value of a, we can take the square root of 144:

a = √144 = 12

Therefore, the length of the missing leg is 12.

Conclusion

In this article, we used the Pythagorean theorem to solve for the length of the missing leg in a right triangle. We started with the given equation, evaluated the powers, undid the addition, and finally undid the square to find the value of the missing leg. The length of the missing leg is 12.

Example Problems

Here are a few example problems that you can try to practice solving for the missing leg using the Pythagorean theorem:

a^2 + 9^2 = 15^2
b^2 + 25^2 = 30^2
c^2 + 36^2 = 40^2

Tips and Tricks

Here are a few tips and tricks to help you solve for the missing leg using the Pythagorean theorem:

Make sure to evaluate the powers correctly.
Undo the addition and subtraction correctly.
Use the square root function to find the value of the missing leg.
Check your work by plugging the value of the missing leg back into the original equation.

Real-World Applications

The Pythagorean theorem has many real-world applications, including:

Building design: Architects use the Pythagorean theorem to design buildings and ensure that the walls and floors are perpendicular.
Engineering: Engineers use the Pythagorean theorem to design bridges and ensure that they are stable.
Physics: Physicists use the Pythagorean theorem to describe the motion of objects and calculate distances and velocities.

Conclusion

Q: What is the Pythagorean theorem?

A: The Pythagorean theorem is a mathematical formula that describes the relationship between the lengths of the sides of a right triangle. It states that the square of the length of the hypotenuse (the side opposite the right angle) is equal to the sum of the squares of the lengths of the other two sides.

Q: How do I use the Pythagorean theorem to solve for the missing leg?

A: To use the Pythagorean theorem to solve for the missing leg, follow these steps:

Evaluate the powers on the left-hand side of the equation.
Undo the addition and subtraction on the left-hand side of the equation.
Use the square root function to find the value of the missing leg.

Q: What is the formula for the Pythagorean theorem?

A: The formula for the Pythagorean theorem is:

a^2 + b^2 = c^2

where a and b are the lengths of the legs of the right triangle, and c is the length of the hypotenuse.

Q: Can I use the Pythagorean theorem to solve for the hypotenuse?

A: Yes, you can use the Pythagorean theorem to solve for the hypotenuse. To do this, rearrange the formula to isolate the hypotenuse:

c = √(a^2 + b^2)

Q: What are some real-world applications of the Pythagorean theorem?

A: The Pythagorean theorem has many real-world applications, including:

Building design: Architects use the Pythagorean theorem to design buildings and ensure that the walls and floors are perpendicular.
Engineering: Engineers use the Pythagorean theorem to design bridges and ensure that they are stable.
Physics: Physicists use the Pythagorean theorem to describe the motion of objects and calculate distances and velocities.

Q: Can I use the Pythagorean theorem to solve for the length of a diagonal?

A: Yes, you can use the Pythagorean theorem to solve for the length of a diagonal. To do this, treat the diagonal as the hypotenuse and the other two sides as the legs.

Q: What are some common mistakes to avoid when using the Pythagorean theorem?

A: Some common mistakes to avoid when using the Pythagorean theorem include:

Not evaluating the powers correctly.
Not undoing the addition and subtraction correctly.
Not using the square root function to find the value of the missing leg.
Not checking your work by plugging the value of the missing leg back into the original equation.

Q: Can I use the Pythagorean theorem to solve for the length of a side in a non-right triangle?

A: No, the Pythagorean theorem only applies to right triangles. If you have a non-right triangle, you will need to use a different formula or method to solve for the length of the side.

Q: How do I know if a triangle is a right triangle?

A: To determine if a triangle is a right triangle, look for the following characteristics:

The triangle has one right angle (90 degrees).
The sum of the squares of the lengths of the legs is equal to the square of the length of the hypotenuse (a^2 + b^2 = c^2).

Q: Can I use the Pythagorean theorem to solve for the length of a side in a triangle with multiple right angles?

A: Yes, you can use the Pythagorean theorem to solve for the length of a side in a triangle with multiple right angles. To do this, treat each right angle as a separate right triangle and use the Pythagorean theorem to solve for the length of the side.

Conclusion

In conclusion, the Pythagorean theorem is a powerful tool for solving for the length of the missing leg in a right triangle. By following the steps outlined in this article and avoiding common mistakes, you can use the Pythagorean theorem to solve for the length of the missing leg and apply it to real-world problems.