The size of a flat-screen tablet is given as the length of the screen’s diagonal. How many square inches greater is the screen of a square 8-inch flat-screen tablet than a square 7 -inch flat-screen tablet? Choose the most appropriate option
A) 7.6  B) 7.3  C) 7.2  D) 7.5  E) 8.0

Rationale: "if we take a square with side length x and draw a diagonal , we get two isosceles right triangles . if we focus on one such right triangle , we see that the legs have length x . square 8 - inch flat - screen television the diagonal ( hypotenuse ) = 8 so , we can apply the pythagorean theorem to get x ² + x ² = 8 ² simplify : 2 x ² = 8 ² divide both sides by 2 to get : x ² = 8 ² / 2 since the area of the square = x ² , we can see that the area of this square is 8 ² / 2 square 7 - inch flat - screen television the diagonal ( hypotenuse ) = 7 so , we can apply the pythagorean theorem to get x ² + x ² = 7 ² simplify : 2 x ² = 7 ² divide both sides by 2 to get : x ² = 7 ² / 2 since the area of the square = x ² , we can see that the area of this square is 7 ² / 2 difference in areas = 8 ² / 2 - 7 ² / 2 = ( 8 ² - 7 ² ) / 2 = ( 64 - 49 ) / 2 = 15 / 2 = 7.5 d"
Answer: D