The calculation method is as follows:

3x√( 1？ + 1.5? ) =5.408 meters

△ABE∽△AED，so: AB:BE=AC:CD。

Using similar triangles principle: hypotenuse of small right triangle: hypotenuse of large right triangle = 1:3.

The ratio of vertical height (H) to horizontal width (L) of a slope is called slope (or slope ratio).

Let the inclination angle be α and the slope be k, then k = h: l = tan α;

The slope is generally written in the form of 1∶m, where m= 1/k and m is called the slope coefficient.

The greater the slope, the greater the slope angle and the steeper the slope. For example, 1: 2 > 1: 3, 1: 2 corresponds to a larger slope angle and a steeper slope.

1: m can be understood as: height = 1, width = m；; That is, the slope = tan α = h: l =1:m.

Properties of Extended Data similar triangles

Defines that the corresponding angles of similar triangles are equal and the corresponding edges are proportional.

Theorem The ratio of any corresponding line segment in similar triangles is equal to the similarity ratio.

Theorem The area ratio of similar triangles is equal to the square of similarity ratio.

Similar triangles's judgment

By analogy with congruent triangles's judgment theorem, we can draw the following conclusions:

Theorem Two angles correspond to two equal triangles respectively.

Theorem Two triangles with proportional sides and equal included angles are similar.

Theorem Two triangles with three sides in proportion are similar.

Theorem A right triangle whose side is proportional to the hypotenuse is similar.