Mr. D'Alton made some radium in his lab. He used 2/5kg of the radium every time he ran his experiment. If he did the experiment four times and had 2 1/3 kg left, how much radium did Mr. D'Alton make at first?​

Prove the converse of the pythagorean theorem using similar triangles. the converse of the pythagorean theorem states that when the sum of the squares of the lengths of the legs of the triangle equals the squares length of the hypotenuse, the triangle is a right triangle. be sure to create and name the appropriate geometric figures.