The extended angle ABC was divided by the ray BD into two angles so that the degree measures of the angles ABD
The extended angle ABC was divided by the ray BD into two angles so that the degree measures of the angles ABD and CBD are related as 5:13. Find the degree measures of the angles ABD and CBD.
If angle ABC is a flat angle, then ∠ABC = 180 °. Angles ABD and CBD are adjacent angles. As you know, together, adjacent angles make up a deployed angle: ∠ABD + ∠CBD = 180 °. By the condition of the task, ∠ABD: ∠CBD = 5: 13. Applying the main property of proportion, we get: 13 * ∠ABD = 5 * ∠CBD, whence ∠ABD = (5/13) * ∠CBD. Substitute this into the expanded angle formula: (5/13) * ∠CBD + ∠CBD = 180 ° or (5/13 + 1) * ∠CBD = 180 °, whence ∠CBD = 180 °: (18/13) = 13 * 180 °: 18 = 130 °. Calculate ∠ABD = (5/13) * ∠CBD = (5/13) * 130 ° = 50 °. Thus, the degree measures of the angles ABD and CBD are 50 ° and 130 °, respectively.