By applying Cathetus theorem, the value of x is equal to 10 units.
<h3>How to determine the value of x?</h3>
In order to determine the value of x, we would apply Cathetus theorem (leg rule), which states that each leg of a right-angled triangle is the geometric mean that's directly proportional between the hypotenuse and the part of the hypotenuse that's directly below the leg.
In this context, we have:
x² = m × a
x² = (21 + 4) × 4
x² = 25 × 4
x² = 100
x = √100
x = 10 units.
Read more on Cathetus theorem here: brainly.com/question/11357448
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