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1)

In a Δ PQR , Let  PQR=300 and the side PQ and QR have lengths 10√3 and 10, respectively . Then , which of the following statement (s) is (are) TRUE?


A) QPR=450

B) The area of the PQR is 253 and QRP=1200

C) The radius of the incircle of the PQR is 10315

D) The area of the circumcircle of the PQR is 100π

Answer:

Option B,C,D

Explanation:

 In  Δ PQR 

          PQR=300

                  PQ = 103    , QR=10

             392019643_new.JPG

By cosine rule

   cos300=PQ2+QR2PR22PQ.QR

  32=300+100PR22003

       300=300+100-PR2

       PR=10

   Since , PR=QR= 10

       QPR=300   and    QRP=1200

Area of ΔPQR = 12 PQ.QR sin300

              =  12×103×10×12=253

Radius of incircle of

            Δ PQR= AreaofPQRSemiperimetreofPQR

 i.e   r=s=253103+10+102=2535(3+2)

         r= 53(23)=10315

       and radius of the circumcircle 

                       (R)=abc4=103×10×104×253=10

   Area of circumcircle of Δ PQR=  πR2=100π

         Hence, option (b), (c) and (d) are correct answer.