Question

I need help I do not know how to do this. First drop down says:Definition of angle bisectoraddition property of Equalityangle addition postulateSecond drop down says:multiplication property of Equalitysubstitution propertyDivision property of Equalitysubtraction property of Equalityaddition property of equality

Answer 1

2) angle addition postulate

3) 129°

5) substitution property

6) 13x - 1

7) 13x = 130

8) x = 10

9) m∠EFI = 40°

Step-by-step explanation:

2) From the angle diagram the sum of both angles give angle GFI

m∠GFE + m∠EFI = m∠GFI

Reason: angle addition postulate

3) Since m∠GFI = 129 degree (given)

m∠GFE + m∠EFI = 129°

5) m∠GFE = (9x - 1)°

m∠EFI = 4x°

9x - 1 + 4x = 129

We substituting the angles with the values given.

Hence, it is substitution property

6) we simplify the expression:

9x -1 + 4x = 129

9x + 4x - 1 = 129

13x - 1 = 129 (combine like terms)

7) Add 1 to both sides:

13x - 1 + 1 = 129 + 1

13x = 130 (addition property of equality)

8) divide both sides by 13:

13x/13 = 130/13

x = 10 (division property of equality)

9) m∠EFI = 4x°

m∠EFI = 4(10)

m∠EFI = 40° (substitution property)