Given PR = 20 , QS = 15 , PR = x , QS = y , angle PTQ = 60 degree

(a)

Find the area of triangle PQT

(b)

Find the area of triangle QRT

(c)

Using (a) and (b), find the area of PQRS

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(a)

triangle PQT =

(b)

triangle QRT =

(c)

don't know how to do (c)

Thanks in advance!