Answer:
b = 19.6
Explanation:
Since this is a right triangle, we can use the Pythagorean theorem
a^2+b^2 = c^2 where a and b are the legs and c is the hypotenuse
20^2+ b^2 = 28^2
400 + b^2 = 784
b^2 = 784-400
b^2 =384
Taking the square root of each side
sqrt( b^2) = sqrt(384)
b =19.59591794
To the nearest tenth
b = 19.6