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Missing complementary angle


Use the applet to practice finding the value of the missing complementary angle. Practice first before you answer the questions You can change the value of <DCE (red angle) by moving the red slider. Notice how the angle is named from the points on the lines with the vertex, C, in the middle. Find the value of <ECB (green angle) and record your answers.

If <DCE is 75°, what is the measure of <ECB?

If <DCE is 32°, what is the measure of <ECB?

If <DCE is 5°, what is the measure of <ECB?

How do you find the missing complementary angle?

Select all that apply
  • A
  • B
  • C
Check my answer (3)