Differentiate both sides wrt 
:
By the chain rule, we get
Solve for 
:
Answer:
QT = RT
Step-by-step explanation:
When drawing triangle PQR the perpendicular bisector cuts the triangle in half, which results in two sides that are congruent. This makes QT and RT congruent.
Since DE is the perpendicular bisector of JL.
The perpendicular bisector is a line that divides a line segment into two equal parts. It also makes a right angle with the line segment. Each point on the perpendicular bisector is the same distance from each of the endpoints of the original line segment.
Since, a perpendicular bisector is a line that divides a line segment into two equal parts.
So, JK=KL. (which is not given in the option)
Since ED is a perpendicular bisector. So, each point on ED is the same distance from the endpoints of line segment JL.
So, EJ=EL.
Therefore, Option 1 is the correct answer.
