Can anyone help as soon as possible?

Describe a way that someone could estime the length of a book

The measures of the legs of a right triangle are 15m and 20m . what is the length of the hypotenuse

Will mark determine whether the conjecture is true or false. give a counterexample for any false conjecture. given: points r, s, and t conjecture: r, s, and t are coplanar. a) false; the points do not have to be in a straight line. b) true c) false; the points to not have to form right angles. d) false; one point may not be between the other two.