Question

M ∠1 = ?

40
50
130

pls help!!

Answer 1

40

Explanation:

In the triangle, there is a 90 degree angle and Angle 1 (what we are looking for) and the other angle, lets call is Angle 2.

Lets find Angle 2 first.

First of all, the angle between angle 40 and 90 can be found easily.

That angle (lets call it "x) and 40 and 90 make a straight angle (180 degrees). So we can write:

40 + x + 90 = 180

Lets solve for "x":

40 + x + 90 = 180

130 + x = 180

x = 180 - 130

x = 50

Now, This angle (50) and Angle 2 are same [vertical angles]

So,

Angle 2 = 50

Now, there are 180 degrees in 3 angles in a triangle. So for the triangle shown, we cacn write:

90 + Angle 1 + Angle 2 = 180

90 + Angle 1 + 50 = 180

Angle 1 + 140 = 180

Angle 1 = 180 - 140

Angle 1 = 40