Question

the sum of the angles of any four-sided figure is 360 degrees. In a quadrilateral, anglea=angle b, angle c is 20 greater than angle a and angle d=40 find the measure of each angle

Answer 1

we suppose angle a=x
b=x
c=x+20
d=40
sum=360
then x+x+x+20+40=360
3x+60=360
3x=360-60
3x=300
x=300/3
=100
then a=100
b=100
c=120
d=40
sum=360

Answer 2

 Let the four angles be a , b, c and d .......

Now  given that  angle a = angle b  ,  angle c = 20 + angle a and angle d = 40

Sum of all angles = 360

angle(a+b+c+d) = 360

angle(a + a + 20 + a + 40 ) = 360

3 angle(a) = 300

angle(a) = 100 = angle (b)

angle(c) = 20 + 100 = 120

angle (d) = 40

now we can verify by adding individual angles..........