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Calculate 3rd Side Isosceles Triangle

Isosceles Triangle Base Formula:

\[ base = 2 \times \sqrt{a^2 - h^2} \]

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1. What is the Isosceles Triangle Base Formula?

The formula calculates the base length of an isosceles triangle when you know the lengths of the two equal sides and the height. It's derived from the Pythagorean theorem applied to one of the two right triangles formed by the height.

2. How Does the Calculator Work?

The calculator uses the isosceles triangle base formula:

\[ base = 2 \times \sqrt{a^2 - h^2} \]

Where:

Explanation: The height divides the isosceles triangle into two congruent right triangles. The formula calculates half the base of one right triangle and doubles it to get the full base.

3. Importance of Base Calculation

Details: Calculating the base is essential for determining the complete dimensions of the triangle, which is important in geometry, construction, and design applications.

4. Using the Calculator

Tips: Enter the length of the equal sides and the height in the same units. Both values must be positive, and the height must be less than the side length.

5. Frequently Asked Questions (FAQ)

Q1: What is an isosceles triangle?
A: An isosceles triangle is a triangle with at least two sides of equal length and two equal angles opposite those sides.

Q2: Can I use this for equilateral triangles?
A: Yes, since an equilateral triangle is a special case of isosceles triangle where all sides are equal.

Q3: What if I know the base and need to find the height?
A: You can rearrange the formula: \( h = \sqrt{a^2 - (base/2)^2} \)

Q4: What units should I use?
A: Any consistent length units (cm, m, inches, etc.) can be used as long as both inputs are in the same units.

Q5: Why does the height need to be less than the side length?
A: In a right triangle formed by the height, the height must be less than the hypotenuse (which is the equal side of the isosceles triangle).

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