How do you prove a triangle with the hypotenuse of length 5 and other sides with lengths 3 and 4 is a right triangle?
109964
the converse of Pythagoras Theorem
97011
Proving that $\prod_{k=1}^{n}\tan\left(\frac{\pi k}{2n+1}\right)=\sqrt{2n+1}$ using geometry
58932
Hard contest type trigonometry proof
27954
Prove triangle inequality using the properties of absolute value
30044
Inequality with triangle sides
118577
Fallacious proof involving trigonometry
84334
How to prove the Pythagoras theorem using vectors
63679
Picture/intuitive proof of $\cos(3 \theta) = 4 \cos^3(\theta)-3\cos(\theta)$?
120953
Show that, $2\arctan\left(\frac{1}{3}\right)+2\arcsin\left(\frac{1}{5\sqrt2}\right)-\arctan\left(\frac{1}{7}\right)=\frac{\pi}{4}$
55779
How to prove: $\left(\frac{2}{\sqrt{4-3\sqrt[4]{5}+2\sqrt[4]{25}-\sqrt[4]{125}}}-1\right)^{4}=5$?
86753
All right angles are equal to each other
132402
Find 2nd leg of right triangle with known leg and perimeter
56878
Proof that $a\mid b \land b\mid c \Rightarrow a\mid c $
73907
Condition for 3 complex numbers to represent an equilateral triangle
30429
How to prove $\cos \frac{2\pi }{5}=\frac{-1+\sqrt{5}}{4}$?
17459
Determining if an arbitrary point lies inside a triangle defined by three points?
2251
Can someone give me a hint on how to prove this?