<p>of the first 50, 25 are negative so you only need to figure out the positive ones and there are only 3 (2, 8, 32) are positive and less than 100. 25+3 = 28</p>
<p>For the second problem it is easier if you can sketch it, but it isn’t bad - you just have to use the pythagorean theorem twice. You have a cube of side length = 2. If you want to find the length of the diagonal across the cube (which is the same as the diameter of the sphere) you need to use the pythagorean theorem - but first you must find the other two sides (the height, which is two) and the diagonal of one of the faces of the cube (which is simply a square) - the diagonal is side length 2 * square root of 2 (by the pythagorean theorem with two shorter sides length 2). So to calculate the diagonal across the cube you have a right triangle with sides 2 and 2<em>square root of 2 and need to figure out the hypotenuse - so by the pythagorean theorem the long side would be 2</em>square root of 3.</p>