Current location - Training Enrollment Network - Mathematics courses - What are the application problems of wall fence in grade three?
What are the application problems of wall fence in grade three?
The application problems of the fence against the wall in grade three are as follows:

1, the farmer's uncle has a rectangular vegetable field 8 meters long and 5 meters wide, surrounded by fences. How long is the fence? If one side is against the wall, how many meters should the fence be at least?

Solution:

( 1)(8+5)×2

= 13×2

=26 (m)

(2)8+5×2

=8+ 10

= 18 (m)

This fence is 26 meters long. If one side is against the wall, the fence should be at least 18 meters.

2. Enclose a trapezoidal vegetable field with a fence. It is understood that the fence is 35 meters long. How many square meters is the area of vegetable field?

Solution: (35-8)×8÷2

=27×8÷2

=2 16÷2

= 108 (m2)

Answer: The vegetable area is 108 square meters.

3. The school plans to enclose a rectangular biological park with a fence with a length of 16m to raise small animals. One side of the biological park is against the wall (as shown in the figure), with a length of 8m and an area of 30m2, thus finding the length and width of the biological park.

Solution: If the width is xm, then the length is (16-2x) m.

X ( 16-2x) = 30,

Solution: x 1=3, x2=5.

When x=3, 16-2x = 10 > 8 (omitted),

When x=5, 16-2x=6.

A: The width of the biological park is 5 meters and the length is 6 meters.