Answer:
15 inches
Step-by-step explanation:A picture frame is rectangular in nature. Therefore a diagonal will divide the frame into two right angled triangles with the diagonal being the longest side of any of the triangle formed. This diagonal is known as the hypotenuse side of the triangle.
to get the hypotenuse of a triangle, we will use the Pythagoras theorem which States that the sum of the square of the adjacent and opposite side of a triangle is equal to the square of the hypotenuse.
If a picture frame is 12 inches long and 9 inches wide, the diagonal of the frame will the serve as the hypotenuse.
Hyp² = Adj²+opp²
If one of the side is 12inches long and the other 9inches long then we can assign adj = 12inches and opposite = 9inchwsHyp² = 12²+9²
Hyp² = 144+81
Hyp² = 225
Hyp = √225
Hypotenuse = 15inches
Since the hypotenuse is 15inches therefore the diagonal is 15inches