Rosalinda examined the angles at right and wrote the equation below.

$(2x + 1°) + (x – 10°) = 90°$

1. Does her equation make sense? If so, explain why her equation must be true. If it is not correct, determine what is incorrect and rewrite the equation.

• Hint (a):

  Is a right angle (as illustrated above), equal to 90°?

  Answer (a):

  Yes. This means Rosalinda's equation makes sense, because the two angles make up a 90° angle.

2. If you have not already done so, solve her equation, clearly showing all your steps. What are the measures of the two angles?

• Hint (b):

  Refer to the Math Notes box in Lesson 1.1.4 if you need help remembering how to solve a linear equation.

3. Verify that your answer is correct.

• Hint (c):

  After solving for x, substitute your answer into the original equation to verify it is correct.