第35問配点 ３点
次の文章は，ある有名な数学者の名前Ｘの付いた定理を英語で説明したものである。この文章が説明しているものとして最も適切な式を，後記１から５までの中から選びなさい。（解答欄は，［№35］）
Ｘ’s theorem describes a relation in Euclidean geometry of the three sides of a right triangle. It states that the square of the hypotenuse (the side opposite the right angle) is equal to the sum of the squares of the other two sides. The theorem can be written as an equation, often called Ｘ’s equation, relating the lengths of the sides a, b and c: （式） where a represents the length of the hypotenuse, and b and c represent the lengths of the other two sides.
１. a + b = c
２. a2 = (b + c)2
３. a2 + b2 = c2
４. a2 = b2 + c2
５. a3 + b3 = c3