Let's do this question in parliament, Graham, BQ are us all is the midpoint of its Q So that means
it's always equal to all.
Q Now we need to find angle s.
Angle R, side B.
Q You are.
And the diagonal PR was the video.
Give it a try and then let's do it together.
All right.
We are back.
I hope you have given it it right now directly.
We can say that P Q is equal to fifteen centimetre and Q are is equal to eleven centimetre.
Right.
Because P Q Ours is a program and in a programme opposite sides are equal.
Right.
But we have these two things.
Now let's press on.
We need to find angle s and angle are all right now.
Angle B will be equal to sixty degrees.
Right.
Why would that be so.
Because well here Espy's parallel to argue and B why is acting as the transversal.
Therefore this angle over here and this angle over here are corresponding angles and they are equal.
Therefore Angle B is equal to sixty degrees.
All right.
Now in a parallel grand we know that are decent, angles are supplementary or they add up to 180 degrees.
Therefore angle B plus angle S is equal to 180 degrees.
Or I can say that angle s is equal to 180 minus sixty.
That's 120 degrees.
All right.
Now over here you can see angle B and other opposite angles.
And in a program, opposite angles are equal.
Therefore, angle are is equal to angle B that sixty degrees.
All right.
Now we have found angle S and we have found angle on.
So these two parts are also done and we are left with finding diagonal.
We are now we can directly solve it.
If you remember the property that in a program diagonals bisect each other, that would mean be always
equal to or and you will get P.
S six in the two, which is twelve centimetre right now.
You can also think of it in this way triangle or P.
Q is congruent triangle or as so these two triangles are congruent.
Right, because let's mark these angles over here.
You will see that angle one and angle two are equal are vertically opposite angles.
Angle for an angle three are equal.
Why.
Because they are alternating angles because SRN and you are parallel and Eskew is acting as the transposon
and you will see that is always equal to Oakhill because it's given right.
Therefore these two triangles are congruent Asper AC criteria.
Now, because these two are congruent, we can see that B R is equal to people plus or and these two
are equal because these two triangles are fondren.
Right.
So that gives you six plus six, which is equal to twelve centimetre.
Now you don't need to do this in the exam because you know that in a program diagonals bisect each other.
So if this is six centimetre definitely.
Or are is also six centimetre and equal and you can directly.
Right.
That bar is equal to twelve centimetre.