∠P=55∘ and QR=18cm if ∠R=35∘,∠P+∠R+∠Q=180∘ ∠Q=180∘−(55∘+35∘)=90∘ Which Contradicts the given statement that△PQRcan be an obtuse scalene triangle Option 1 is incorrect. Take Option 2:
∠R=25∘,∠P=55∘ ∠Q=180∘−(25∘+55∘)=100∘ But side opposite to the smallest Angle is Largest which means PQ should be greater than 18 cm but PQ=18cm Hence, Option 2 is incorrect. Take Option 4:
∠R=65∘,∠P=55∘ ∠Q=180∘−(65∘+55∘)=60∘which Contradicts the statement that △PQR can be an obtuse scalene triangle and alsoPQ>18cmContradicts that side opposite to the Largest angle is smallest Hence, Option 4 is Incorrect.