Question

In the accompanying diagram, points A, E, and B are collinear, measure of angle A= 30, measure of angle DEB= 130, and segment AB is perpendicular to segment BC. Find the measure of angle C and the measure of angle D.

Answer 1

Explanation:

I assume the points D, E and C are also collinear (are on the same straight line).

that is something your teacher forgot to mention. but it is essential.

we have to remember :

1. the sum of all angles in a triangle is always 180°.

2. the sum of all angles around a single point on one side of a line is also always 180°.

3. the angles at the intersection point of 2 lines are the same on both sides of any of the intersecting lines, but they are left-right mirrored.

so,

angle A = 30°

angle DEB = 130°, so,

angle AED = 180 - DEB = 180 - 130 = 50°.

therefore, angle BEC = AED = 50°

therefore, angle D = 180 - 30 - 50 = 100°.

we know, angle B = 90° (AB is perpendicular to BC).

therefore,

angle C = 180 - 90 - 50 = 40°