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Easier Temple Geometry Problems
Problem 13 Watanabe Kiichi proposed this problem, which is the twelfth from the right on the Abe no Monjuin sangaku, color plate 11. As shown in figure 4.12, an equilateral triangle with side t, a square of side s and a circle touch each other in a right triangle ABC with vertical side a. Find t in terms of a. Answer: t = ( 3 − 1)a . The solution can be found on page 124. B
s a t
Figure 4.12. Find t in terms of a. C
A
Problem 14 Proposed by Yamasaki Tsugujirou, this problem is the second problem from the right on the Meiseirinji tablet, color plate 8. In a rhombus, there are two red circles of radius r, two white circles of radius r 1, and five blue circles of radius r 2 (see figure 4.13.). Show that r 2 = r 1/2, or blue = white/2. A full solution to the problem is given on page 124.
Figure 4.13. Show that the radius of the “blue” circles (dark) is one-half the radius of the “white” circles (white).