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# Euclidean Geometry Triangles

They say triangles are the simplest polygon, but they're still not all that simple. Dive into this advanced treatment of triangles, and learn beautiful results from Euler's line to Routh's Theorem.

# Area of Triangles - Heron's Formula

What is the area of a triangle with side lengths $$9,12,$$ and $$15?$$

What is the area of a triangle with side lengths $$13, 14,$$ and $$15?$$

What is the area of a triangle with side lengths $$9, 11,$$ and $$10?$$

A triangle has perimeter 14 and area $$2\sqrt{14}.$$ If the shortest side has length 3, find the positive difference between the lengths of other two sides. Give your answer to 3 decimal places.

What is the area of a triangle with side lengths $$3,5,$$ and $$7?$$

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