A right triangle has one angle that measures $20°$. What is the measure of the other acute angle?

• A. $80°$
• B. $70°$
• C. $90°$
• D. $60°$

Answer: (B)

Verified step by step guidance

1. Recall that the sum of the interior angles in any triangle is \(180^\circ\).
2. Since the triangle is a right triangle, one of its angles measures \(90^\circ\).
3. Let the given acute angle be \(20^\circ\) and the other acute angle be \(x\) degrees.
4. Set up the equation for the sum of angles: \(90^\circ + 20^\circ + x = 180^\circ\).
5. Solve for \(x\) by subtracting \(90^\circ\) and \(20^\circ\) from \(180^\circ\): \(x = 180^\circ - 90^\circ - 20^\circ\).