After a figure is enlarged or reduced, the shape of the figure must have changed due to the change of all sides

After a figure is enlarged or reduced, the shape of the figure must have changed due to the change of all sides

No, the shape doesn't change, just the size

When zooming in or out, the shape () of the figure and the size () of the figure

When a figure is enlarged or shrunk, its shape (unchanged) and size (changed)

When an object (or a figure) is translated from one position to another, the -- and -- of the figure do not change, but only the -- of the figure changes

The shape and size remain unchanged
Position change

As shown in the figure, translate △ PQR to △ P ′ Q ′ R ′ along the direction of PQ. The area of their overlapping parts is half of the area of △ PQR. If PQ = 2, the distance PP ′ of the triangle is ()
A. 12B. 22C. 1D. 2−1

According to the meaning of the title, we can get that the ratio of △ PQR ∽ P ′ Q ′ R ′, ∵ area is equal to the square of the similarity ratio; ∵ P ′ QPQ) 2 = 12, ∵ P ′ q = 2 × 22 = 1; ∵ moving distance PP ′ = 2-1

Ten cubes with ACM edge length are placed in the shape as shown in the figure. What is the surface area of the figure?

Ten cubes with ACM edge length are placed in the shape as shown in the figure. What is the surface area of the figure?

In △ ABC, ∠ C = 90 °, ad bisection ∠ BAC intersects BC with D, and BD: CD = 3:2, BC = 15cm, then the distance from point d to AB is______ ．

According to the properties of angular bisector, the distance from point d to AB is CD, ∵ BD: CD = 3:2, BC = 15. Let BD = 3x, then CD = 2x, BD + CD = BC = 15, that is, 3x + 2x = 15. The solution is x = 3, ∵ CD = 2x = 6cm

According to the national standard, the ratio of teachers to students is 1:19
Has the number of teachers reached the national standard? If not, how many are left behind?
Please give the solution of each formula,
The number of students is 1755

There are 1755 students in Xinhua primary school. According to the ratio of 1:19, there should be 1755 △ 19 ≈ 93 teachers. The title tells us that there are 89 teachers, so they don't meet the standard. The difference is 93-89 = 4

The excellent teachers in Xinhua primary school account for 10% of the total number of teachers, and the excellent teachers in happy primary school account for 15% of the total number of teachers. Can we compare the number of excellent teachers in which primary school?

The number of excellent teachers in Xinhua primary school = all teachers × 10%, and the number of excellent teachers in happy primary school = all teachers × 15%. Because there is no specific data given in the total number of teachers in Xinhua primary school and happy primary school, the number of excellent teachers in the two primary schools can not be compared

The excellent teachers in Xinhua primary school account for 10% of the total number of teachers, and the excellent teachers in happy primary school account for 15% of the total number of teachers. Can we compare the number of excellent teachers in which primary school?

The number of excellent teachers in Xinhua primary school = all teachers × 10%, and the number of excellent teachers in happy primary school = all teachers × 15%. Because there is no specific data given in the total number of teachers in Xinhua primary school and happy primary school, the number of excellent teachers in the two primary schools can not be compared