【趣味数学题】 新算额题（四） Revival of Sangaku 4

郑涛提出的问题

图： 如图 1 所示，在灰色大正方形内有 1 个青色正方形和 4 个红色正方形。

命题：假设大正方形的面积是50，青色正方形的面积是29。求一个红色正方形的面积。

Problem created by Tao Steven Zheng

Diagram: There is a large grey square. Inside the large grey square there is one blue square and four red squares as shown in Figure 1.

Problem: Suppose the area of the large square is 50 and the area of the blue square is 29. Determine the area of the red square.