Question

What is the measure of angle B?

Answer 1

39.6

Explanation:

(3x-15)+(4x+20)+2x=360

9x+5=360

9x=355

*Divide each side by 9*

X=39.4

*SUBSTITUTE X*

3(39.4)-15=103.2

4(39.4)+20=177.6

*ADD THE TOTALS FROM ABOVE*

103.2+177.6= 280.8

360-280.8=79.2

*DIVIDE THE TOTAL BY 2*

79.2/2=39.6

*CHECK*

3(39.4)-15=103.2

4(39.4)+20=177.6

103.2+177.6+39.6+39.6=360 IS CORRECT.

Hope this helps! :)

Answer 2

m∡B = 120°

Explanation:

base angles are equal

adjacent angles are supplementary so:

4x+20 + 3x-15 = 180

7x + 5 = 180

7x = 175

x = 25

∡B = 4(25) + 20

∡B = 120°