If AB, AC, PQ are tangents in the given figure and AB = 5 cm, find the perimeter of Δ APQ.
We have been asked to find the perimeter of the triangle APQ.
Therefore,
Perimeter of ΔAPQ is equal to AP + AQ + PQ
By looking at the figure, we can rewrite the above as follows,
Let the Perimeter of ΔAPQ be P. So P= AP + AQ + PX + XQ
From the property of tangents we know that when two tangents are drawn to a circle from the same external point, the length of the two tangents will be equal. Therefore we have,
PX =PB
XQ =QC
Replacing these in the above equation we have,
P =AP + AQ + PB + QC
From the figure we can see that,
AP + PB = AB
AQ + QC = AC
Therefore, we have, P= AB + AC
It is given that AB = 5 cm.
Again from the same property of tangents we know that that when two tangents are drawn to a circle from the same external point, the length of the two tangents will be equal. Therefore we have,
AB = AC
Therefore,
AC = 5 cm
Hence,
P = 5 + 5=10
Thus the perimeter of triangle APQ is 10 cm.