Question

Лампа S, расположенная у края стола, и шахматная фигура AB высотой 10 см находятся на прямой, перпендикулярной к плоскости экрана Э. На каком расстоянии от лампы отстоит экран, если на нем высота тени от фигуры равна 30 см, а SB=40 см. ​

Answer 1

Ответ:

Ответ в файле ,, ответ в файле

Объяснение:

Answer 2

Problem Analysis

We are given the following information: - A lamp S is located at the edge of a table. - A chess piece AB with a height of 10 cm is on a straight line perpendicular to the screen plane. - The height of the shadow of the chess piece on the screen is 30 cm. - SB, the distance between the chess piece and the screen, is 40 cm.

We need to find the distance between the lamp and the screen.

Solution

To solve this problem, we can use similar triangles. Let's denote the distance between the lamp and the screen as LS.

We have two similar triangles: triangle LSA and triangle ABE.

The height of the shadow on the screen (AE) is 30 cm, and the height of the chess piece (AB) is 10 cm. The distance between the chess piece and the screen (SB) is 40 cm.

Using the property of similar triangles, we can set up the following proportion:

LS / SB = AE / AB

Substituting the given values, we get:

LS / 40 = 30 / 10

Simplifying the equation, we have:

LS / 40 = 3

To find LS, we can cross-multiply and solve for LS:

LS = 40 * 3

Therefore, the distance between the lamp and the screen is 120 cm.

Conclusion

The distance between the lamp and the screen, given that the height of the shadow of the chess piece is 30 cm and SB is 40 cm, is 120 cm.