Problem
Let ABCD be a convex cyclic quadrilateral . Suppose P is a point in the plane of the quadrilateral such that the sum of its distances from the vertices of ABCD is the least .If {PA,PB,PC,PD} = {3,4,6,8}.What is the maximum possible area of ABCD?
Topic
Geometry
Contest
Pre Regional Math Olympiad
2019
Reading
Mathematical circle .
Sequential Hints
The first step is very clear, you have to some how locate the point P .
claim : The intersection of the diagonal is the required point .
Proof : suppose that there is a point P' other than P (the intersection of diagonal) .
now try to apply triangular inequality in \(\triangle\)PBD & \(\triangle\)APC.
(do the rest yourself , and complete the proof)
so , the area of [ABCD]=\(\frac{1}{2}\)\(\sin\theta\)(PA*PB+PB*PC+PC*PD+PD*PA)
now, the area will maximum when \(\sin\theta\)=1
so , just put the value of PA, PB, PC,PD
You get the answer 55
Watch video
Problem
Let ABCD be a convex cyclic quadrilateral . Suppose P is a point in the plane of the quadrilateral such that the sum of its distances from the vertices of ABCD is the least .If {PA,PB,PC,PD} = {3,4,6,8}.What is the maximum possible area of ABCD?
Topic
Geometry
Contest
Pre Regional Math Olympiad
2019
Reading
Mathematical circle .
Sequential Hints
The first step is very clear, you have to some how locate the point P .
claim : The intersection of the diagonal is the required point .
Proof : suppose that there is a point P' other than P (the intersection of diagonal) .
now try to apply triangular inequality in \(\triangle\)PBD & \(\triangle\)APC.
(do the rest yourself , and complete the proof)
so , the area of [ABCD]=\(\frac{1}{2}\)\(\sin\theta\)(PA*PB+PB*PC+PC*PD+PD*PA)
now, the area will maximum when \(\sin\theta\)=1
so , just put the value of PA, PB, PC,PD
You get the answer 55
Watch video
