Sample Response: You could use the Pythagorean theorem, since you know the length of the hypotenuse is 9 + 16 = 25 units and the length of one leg is 15 units. To find the value of a, use the relationship that the the square of the length of the hypotenuse is equal to the sum of the squares of the lengths of the legs. You could also use the geometric mean (leg) theorem, which states that the length of the hypotenuse is to the length of an adjacent leg as that adjacent leg length is to the length of its corresponding segment in the hypotenuse. So you could write and solve the proportion 25/a = a/6.
See the attached figure to better understand the problem
we know that
1) First way to find the value of a in the triangle ABC <span>applying the Pythagorean theorem AC</span>²=AB²+BC²--------> BC²=AC²-AB²-----> BC²=25²-15²-----> BC²=625-225 BC²=400--------> BC=20 units a=BC a=20 units
2) Second way to find the value of a
in the triangle ABD
AB²=AD²+BD²--------> BD²=AB²-AD²-----> BD²=15²-9²---> BD²=144 BD=12 units
in the triangle BDC a=BC BC²=BD²+DC²-----> 12²+16²----> 144+256------> BC²=400 BC=20 units a=20 units