Step 1: Calculate the squares of the known numbers.
$$38^2 = 38 \times 38 = 1444$$
$$63^2 = 63 \times 63 = 3969$$
Step 2: Substitute the calculated squares into the equation.
$$1444 + 3969 + (?)^2 = 6089$$
Step 3: Add the known numbers.
$$1444 + 3969 = 5413$$
So, the equation becomes:
$$5413 + (?)^2 = 6089$$
Step 4: Isolate the term with the question mark.
Subtract 5413 from both sides of the equation:
$$(?)^2 = 6089 - 5413$$
$$(?)^2 = 676$$
Step 5: Solve for the question mark by taking the square root.
$$? = \sqrt{676}$$
$$? = 26$$