Concept:The sum of the interior angles of any quadrilateral is always 360∘.Explanation:Write the equation for the sum of the four given angles:(x+15)∘+(2x−45)∘+(x−30)∘+(x+10)∘=360∘Remove the degree symbols and combine like terms:x+15+2x−45+x−30+x+10=3605x−50=360Solve for x:5x=360+505x=410x=82Substitute x=82 into each angle expression:x+15=82+15=97∘2x−45=2(82)−45=119∘x−30=82−30=52∘x+10=82+10=92∘The four interior angles are 97∘, 119∘, 52∘, and 92∘.The least among them is 52∘.Answer:D. 52∘