Angle ACB and angle BCD are supplementary. The measure of angle ACB = (5x) degrees and the measure of angle BCD = (2x + 5) degrees. What is the measure of angle BCD?

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55 degrees
125 degrees
25 degrees
75 degrees

1 answer

To find the measure of angle BCD, we start with the information that angles ACB and BCD are supplementary, meaning their measures add up to 180 degrees.

Given:

  • Measure of angle ACB = \(5x\) degrees
  • Measure of angle BCD = \(2x + 5\) degrees

Setting up the equation based on the supplementary angles: \[ 5x + (2x + 5) = 180 \]

Now, we can simplify the equation: \[ 5x + 2x + 5 = 180 \] \[ 7x + 5 = 180 \]

Next, we will isolate \(x\): \[ 7x = 180 - 5 \] \[ 7x = 175 \] \[ x = \frac{175}{7} \] \[ x = 25 \]

Now, we can find the measure of angle BCD by substituting \(x\) back into its expression: \[ \text{Measure of angle BCD} = 2x + 5 \] \[ = 2(25) + 5 \] \[ = 50 + 5 \] \[ = 55 \text{ degrees} \]

Thus, the measure of angle BCD is \(\boxed{55}\) degrees.