The way to do it can be explained like this:
Say AB and CD are the two parallel lines cut by a transversal at E and F respectively.
Then the pairs of alternate interior angles are:
Angle(AEF) and Angle(DFE)
Angle(CFE) and Angle(BEF)
Now lets prove if this is true:
<span>Angle(CFE) +Angle(DFE) = 180
(linear pair)
Also
Angle(CFE) +Angle(AEF) = 180
(Corresponding angles)
</span><span>Equate the above results:
Angle(CFE) +Angle(DFE) = Angle(CFE) +Angle(AEF)
</span><span>Angle(DFE) = Angle(AEF)
</span>Happens the same with
<span>Angle(CFE) = Angle(BEF)
</span>Hope this is very useful for you
I can help you. Just post the question
<span>Ishaan is 21, Christopher is 7
No actual question given, but I will assume that the question is "How old are they?". If that's the case, we can create two equations. I'll use I for Ishaan's age and C for Christopher's. I will also assume that there's been some formatting issues here and for some reason, numbers are repeated 3 times without any spaces. So
"Ishaan is 3 times as old as Christopher"
I = 3C
"is also 14 years older than Christopher
I = C + 14
Since both equations are equal to each other, let's set them equal. So
3C = C + 14
2C = 14
C = 7
So Christopher is 7. And we can use the equation I = C + 14 to get Ishaan's age. So
I = C + 14
I = 7 + 14
I = 21</span>