If one side of the triangle is 3 cm, and the hypotenuse is 5cm, then the other side is 4cm because of Pythagorean triples. Or you can use the Pythagorean theorem which is a^2+b^2=c^2. In this case, c=5, a=3. So it would be 9+b^2=25. b^2=16, and b=4. Then you find the area of the triangle. The formula for area of any triangle is height times base divided by two. (h times b)/2. So the height and the base are 3 and 4. 3 times 4=12, and 12 divided by 2 is 6. So the area of CAT is 6 cm squared.
