If m∠F=40° then m∠D=40°
m∠F, m∠D and m∠G have to be 180° together in order to form a triangle
So m∠G = 180° - 2×40° = 100°
One line is cutting m∠G in half and we get m∠EGF and m∠EGD
We want to know how much m∠EGF is so...
m∠EGF=100°÷2=50°
Now we have m∠F which we can name m∠EFG and we have m∠EGF
Together with m∠FEG they form a triangle so that means together they have the value of 180°
m∠FEG=180°-40°-50°=90°
And because you have parralel lines m∠FEG=m∠CBE
And m∠ABE=180°-m∠CBE=90°
That is if I understand this correctly
[tex]m∠abe = 90[/tex]
