Answer:
19.8 cm
Explanation:
Using the Pythagorean theorem , the Square of the distance between the top of the piece and the Shadow Is the sum of the height of the piece. and the lenght of the shadow. basically Just build a triangle with the 3 points you are given: height of the piece, lenght of the shadow and distance between the 2. so it's sqrt(13^2+15^2) = sqrt(394) =19.8 cm