Answer:
c = 20
Explanation:
Given that,
A rectangle PQRS,
QT = c and ST = 4c-60
We need to find the value of c.
We know that the diagonals of a rectangle bisect each other such that,
QT = ST
Putting values,
c = 4c - 60
Taking like terms together,
60 = 4c - c
60 = 3c
c = 20
Hence, the value of c is 20.