00:01
For part 1, angle klj and angle j1 are equal.
00:05
They're both equal to x because they're the base angle of the isosceles triangle kjl.
00:12
And we also have angle jnk is equal to angle klj.
00:19
Because these two angles are subtended by the same arc.
00:23
The arc is jk.
00:28
So these two angles are equal to x.
00:31
For part 2, we know that angle j3 is equal to angle jmn because both angles are the base angles of the associable triangle jmn.
00:45
And we also know that angle n1 and angle klj are equal because both angles are subtended by the same arc.
00:54
They're both equal to x.
00:57
And angle k1 is equal to angle jmn because both angles are subtended by the same arc.
01:05
Now let's look at angle p2, which is equal to angle j3 plus angle n1, because p2 is an exterior angle of triangle pjn.
01:17
And j3 and n1, these two angles are the remote interior angles of that triangle.
01:28
So angle p2 is equal to the sum of these two interior angles.
01:34
And j3 is equal to jmn.
01:38
N1 is equal to x...