In a right triangle, if one of the acute angles is $a$, what expression represents the measure of the other acute angle $x$?

• A. $2a$
• B. $90-a$
• C. $180-a$
• D. $\frac{a}{2}$

Answer: (B)

Verified step by step guidance

1. Recall that in a right triangle, the sum of the three interior angles is always 180 degrees.
2. Since one angle is a right angle, it measures 90 degrees.
3. Let the two acute angles be \( a \) and \( x \). Because the sum of all angles is 180 degrees, we have the equation: \( a + x + 90 = 180 \).
4. To find the expression for the other acute angle \( x \), isolate \( x \) by subtracting \( a \) and 90 from both sides: \( x = 180 - 90 - a \).
5. Simplify the right side to get \( x = 90 - a \), which represents the measure of the other acute angle.