Show ALL your calculations.

<DEB= 125 degrees

Step-by-step explanation:

To get this, you would need to know all 2 angles of the triangle.

To find the first angle, simply do 180-107 to get 73(because supplementary angles add up to 180 degrees).

Next, 180-52(given angle)-73 to get 55 because the 3 angles of a triangle add up to 180(triangle angle sum theory).

You would see that <DEB is part of another supplementary angle so, do 180-55 to get 125.

<DEB=125 degrees.

125 is the answer.

Step-by-step explanation:

Let's calculate all the internal angles in the triangle 1st.

∠ACE + ∠ECB =180

107 +∠ECB =180

∠ECB =73

The sum of internal angles in a triangle is 180 so

∠ECB +∠EBC +∠CEB =180

73+52+∠CEB=180

∠CEB=180-125

∠CEB = 55

Since CB is a line

∠CEB +∠DEB =180

55+∠DEB =180

∠DEB=125