Answer:
58°
Explanation:
to find m∠CEB
triangle CEB is formed by the two parts of rectangle diagonals (and BC), and as we know, diagonals bisect each other, thus EB is congruent to EC, and it is an isosceles triangle
We also know that angles opposite congruent sides are congruent, thus,
angles EBC and ECB are congruent
thus angle ECB= 61°
We know that the inner angle measures of a triangle according to Angle Sum Theorem add up to 180°
Thus,m angle EBC + m angle ECB + m angle CEB= 180
Now we know that both EBC and ECB are angles with the measure of 61 °, so lets put the measures in instead of angles into the equation
61+61+m angle CEB=180
122 + m angle CEB =180
m angle CEB=180-122
m angle CEB=58°