Question

Enter the number that belongs in the green box.

Answer 1

We know that angle B is 80 degrees since all angles in a triangle add up to 180 degrees.

70 + 30 + B=180, B=80

And we know that B=D since the two triangles are similar

Therefore angle D=80 degrees

Answer 2

Angle D equals 80 degrees.

Since both triangles and angles are congruent, you can use triangle ABC to find the measure of CDE.

ABC has to equal 180 degrees so that means that 30 + 70 + <B = 180

add: 100 + <B = 180

Subtract <B = 80

Angle B equals 80 degrees which also means that Angle D equals 80 degrees.