Answer:
a = 6
b = 25
Explanation:
As alternative angles in a parallel line are equal to each other,
5a = 3a + 12
So, now we can find the value of a by making "a" the subject.
5a - 3a = 12
2a = 12
Divide both sides by 2.
a = 6°
And now let us find the value of b.
We know that interior angles in a triangle are added up to 180°.
So,
2b + 4b + 3a + 12 = 180
We can replace a with 6 and then we can make "b" the subject to find the value of b.
Let us solve it now.
2b + 4b + 3 × 6 + 12 = 180
6b + 18 + 12 = 180
6b + 30 = 180
6b = 180 - 30
6b = 150
Divide both sides by 6.
b = 25°