Answer:
m∠1 = 50°
Explanation:
From inspection of the given diagram we can see that angle 1, angle 40° and a right angle are the interior angles of a right triangle.
As the interior angles of a triangle sum to 180°:
⇒ m∠1 + 40° + 90° = 180°
⇒ m∠1 + 130° = 180°
⇒ m∠1 + 130° - 130° = 180° - 130°
⇒ m∠1 = 50°
Therefore, the measure of angle 1 is 50°.