Question

Найти периметр, если известно что.... а)одна сторона прямоугольника равна 8 дм 6 см, а другая сторона на 5 см больше. б)длина прямоугольника равна 15 см 4мм а ширина в 2 раза меньше. в)сторона квадрата равна 3м27см. г)ширина стола равна 1м20см а длина в 2 раза больше. д)длина прямо-ка участка земли равна 2км 400м.а ширина на 560м меньше...помогите 4 класс

Answer 1

А)1)86см(8дм6см)+5см=91см-другая сторона.
   2)P=86*2+91*2=172+182=354см=35дм4см
б)1)154мм:2=77мм-ширина
   2)P=154*2+77*2=308+154=462мм=4дм6см2мм
в)P=327см*4=1308см=13м8см
г)1)120*2=240см-длина
   2)P=120*2+240*2=240+480=720см=7м20см
д)1)2400-560=1840м-ширина
   2)P=2400*2+1840*2=4800+3680=8480м=8км480м
   

Answer 2

Calculation of Perimeter

a) In the first case, one side of the rectangle is 8 dm 6 cm, and the other side is 5 cm longer.

To find the perimeter, we need to add up all the sides of the rectangle.

Let's calculate the perimeter step by step:

- The first side is 8 dm 6 cm. - The second side is 5 cm longer than the first side, so it is 8 dm 6 cm + 5 cm. - The third side is the same as the first side, 8 dm 6 cm. - The fourth side is the same as the second side, 8 dm 6 cm + 5 cm.

Now, let's calculate the perimeter using the formula P = a + b + c + d, where a, b, c, and d are the lengths of the sides of the rectangle.

P = 8 dm 6 cm + (8 dm 6 cm + 5 cm) + 8 dm 6 cm + (8 dm 6 cm + 5 cm)

P = 2 * (8 dm 6 cm + 8 dm 6 cm + 5 cm + 5 cm)

P = 2 * (16 dm 12 cm + 10 cm)

P = 2 * (16 dm 22 cm)

P = 2 * 28 dm

P = 56 dm

Therefore, the perimeter of the rectangle is 56 dm.

b) In the second case, the length of the rectangle is 15 cm 4 mm, and the width is 2 times smaller.

To find the perimeter, we need to add up all the sides of the rectangle.

Let's calculate the perimeter step by step:

- The length of the rectangle is 15 cm 4 mm. - The width is 2 times smaller than the length, so it is (15 cm 4 mm) / 2.

Now, let's calculate the perimeter using the formula P = 2 * (a + b), where a and b are the lengths of the sides of the rectangle.

P = 2 * (15 cm 4 mm + (15 cm 4 mm) / 2)

P = 2 * (15 cm 4 mm + 7 cm 52 mm)

P = 2 * (22 cm 56 mm)

P = 2 * 28 cm

P = 56 cm

Therefore, the perimeter of the rectangle is 56 cm.

c) In the third case, the side of the square is 3 m 27 cm.

To find the perimeter of a square, we need to multiply the length of one side by 4.

Let's calculate the perimeter:

P = 4 * (3 m 27 cm)

P = 4 * 3 m 27 cm

P = 12 m 108 cm

Since 1 m = 100 cm, we can convert 108 cm to meters:

P = 12 m + 1 m 8 cm

P = 13 m 8 cm

Therefore, the perimeter of the square is 13 m 8 cm.

d) In the fourth case, the width of the table is 1 m 20 cm, and the length is 2 times longer.

To find the perimeter, we need to add up all the sides of the rectangle.

Let's calculate the perimeter step by step:

- The width of the table is 1 m 20 cm. - The length is 2 times longer than the width, so it is 2 * (1 m 20 cm).

Now, let's calculate the perimeter using the formula P = 2 * (a + b), where a and b are the lengths of the sides of the rectangle.

P = 2 * (1 m 20 cm + 2 * (1 m 20 cm))

P = 2 * (1 m 20 cm + 2 m 40 cm)

P = 2 * (3 m 60 cm)

P = 2 * 4 m

P = 8 m

Therefore, the perimeter of the rectangle is 8 m.

e) In the fifth case, the length of the straight section of land is 2 km 400 m, and the width is 560 m smaller.

To find the perimeter, we need to add up all the sides of the rectangle.

Let's calculate the perimeter step by step:

- The length of the straight section of land is 2 km 400 m. - The width is 560 m smaller than the length, so it is 2 km 400 m - 560 m.

Now, let's calculate the perimeter using the formula P = 2 * (a + b), where a and b are the lengths of the sides of the rectangle.

P = 2 * (2 km 400 m + (2 km 400 m - 560 m))

P = 2 * (2 km 400 m + 1 km 840 m)

P = 2 * (4 km 240 m)

P = 2 * 5 km

P = 10 km

Therefore, the perimeter of the rectangle is 10 km.

Note: The calculations are based on the given information.