Right triangle: fill any two of a, b (legs) and c (hypotenuse), leave the unknown blank.
Enter both legs (a and b) and leave c blank. The calculator returns c = sqrt(a squared + b squared).
Yes. Enter the hypotenuse c and one leg, leave the other leg blank; it solves the missing leg as sqrt(c squared minus leg squared). The hypotenuse must be the longest side.
For a right triangle, the square of the hypotenuse equals the sum of the squares of the two legs: a squared + b squared = c squared.