To solve these problems we will use the Pythagorean Theorem( a²+b²=c², where a and b are the legs and c is the hypotenuse). Let's start! ----------------------------------------------------------------------------------------- Q. 7 5²+12²=c² 25+144=169 √169=13 The length of the hypotenuse is 13. ----------------------------------------------------------------------------------------- Q. 8 We already know the length of the hypotenuse, so we will have to solve for a by subtracting. 10²-8²=a² 100-64=36 √36=6 The length of the missing leg is 6. --------------------------------------------------------------------------------------- Q. 9 To test whether or not this is a right triangle, we have to make sure the squares of the legs is equal to the square of the hypotenuse. The hypotenuse is ALWAYS the longest side of a triangle, so in our case, the hypotenuse is eight. Let's check the squares. 16+49=65 16+49≠64 Therefore, this is NOT a right triangle. I hope this helps!