A Pythagorean Theorem of Grade Two, Urgent!

Before lifting the flat swing, the pedal is one foot off the ground, and the two steps to send you are the same as others, remember the five-foot man; Ladies and beautiful women struggle for success, and eventually they are laughed at by jokes. Good teachers and teachers are curious. How long do you think it will take?

(Note: Ancient 1 step =5 feet)

Translated into modern Chinese, the general idea is:

When the swing is still hanging, the height of the pedal from the ground is 1 foot. Now shake out the distance of two steps. Someone recorded that the height of the pedal was 5 feet from the ground. Celebrities and beautiful women compete to swing and laugh all day; The craftsmen are curious about how long the swing rope is.

Answer: It can be calculated that the chord length of the swing sector is the root sign (100+ 16)=2 root signs (29).

From the vertical line with the center of the circle as the chord, it can be known that the chord tangent angle is equal to half of the central angle, and the obtained right triangle is similar to the triangle where the chord tangent angle is located. The radius (that is, the rope length) can be obtained from the proportional relationship of the corresponding line segments as follows.

L=R= 14.5 feet.

That is, the rope length is 14.5 feet.

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