One of the triangles (that on the left, top) has 2 equal sides, and thus is isosceles. The angle immediately adjacent to and to the right of 110 degrees is 180-110 degrees, or 70 degrees, which means that angle 1 is also 70 degrees. The remaining angle is 180 degrees less 2(70 degrees), or 40 degrees; thus, angle 2, immediately adjacent to and to the right of this 40 degree angle, is 180-40, or 140 degrees. The triangle to the right and below the horiz. line has angle 40 degrees (using the principle of vertical angles); thus, angle 3 is 180-(40+90) degrees, or 50 degrees.
1st triangle (left) This is an isosceles triangle. 1) The angle near 110⁰ is (180-110)= 70⁰. 2)m ∠ 1 = 70⁰, because this triangle is isosceles. 3) (180 - m∠2)
Sum of three angles 70 + 70 + 180 - m∠2 =180 70+ 70 - m∠2 = 0 m∠2 = 140⁰ Second triangle (right) 1) (180 - m∠2) 2) m∠ 3 3) 90⁰
Sum of three angles 180 - m∠2 +m∠3+90 = 180 - 140 +m∠3+90 = 0 m∠3 = 50⁰
