If x=100, what is the value of y ?

The value of y° = 80°

Step-by-step explanation:

Given

m∠A = 20

m∠B = x°

as

x = 100,

so

m∠B = 100

We know that the sum of angles of a triangle is 180°.

Thus, the m∠C of the triangle ABC can be calculated as:

m∠A + m∠B + m∠C = 180°

20° + 100° + m∠C = 180°

                    m∠C = 180° - 120°

                              = 60°

As we know that Vertical angles are always congruent.

In other words, m∠C is common in both triangles ΔABC and ΔCDE

m∠C = 60°

m∠E is also given.

i.e. m∠E = 40°

as

m∠D = y°

So, we have to determine m∠D in order to determine y°.

We know that the sum of angles of a triangle is 180°.

Thus, using the values of the angles ΔCDE

i.e.

m∠C + m∠D + m∠E = 180°

60° + y° + 40° = 180°

y° = 180° - 100°

y° = 80°

Therefore, the value of y° = 80°

10 - 8 = -2

  8 - 6 = -2

etc, so -2 is the common difference

step-by-step explanation: