∠PQR = 90° Remember: Radius is perpendicular to the tangent at the point of contact. In ΔPQR, PQ = QR = r ⇒ ∠QRp = ∠QPR = 45° Remember: Equal sides have equal angles opposite to them. Area of the part of the triangle which is outside the circular region = Area of the ΔPQR – Area of the sector PQRP