The missing exterior angles each form a straight angle with an interior angle.
What is the measure of a straight angle?
You will need to find the angle that forms a linear pair with ∠d.
If a quadrilateral can be made into two triangles, what is the sum of the interior angles of a quadrilateral?
a = 87º, b = 83°, c = 96° d = 94º,
∠a + ∠b +∠c + ∠d = 360°