Question

Вычислите: 2,66 : 3,8 – 0,81 × 0,12 + 0,0372. 7,8 × 0,26 – 2,32 : 2,9 + 0,672. В магазине 240 кг фруктов. За день продали 65 % фруктов. Сколько килограммов фруктов осталось? В цистерне 850 л молока. 48 % молока разлили в бидоны. Сколько молока осталось в цистерне? Найдите высоту прямоугольного параллелепипеда, объем которого равен 25,2 дм3, длина 3,5 дм и ширина 16 см. Объем прямоугольного параллелепипеда 1,35 м3, высота 2,25 м и длина 8 дм. Найдите его ширину. 6. Найдите неизвестное: 2,3у + 31+ 2,5у = 67. 13 + 3,2х + 0,4х = 40. 7. Постройте углы МОК и КОС, если ÐМОК = 110°, ÐКОС = 46°. Какой может быть градусная мера угла СОМ ? 8. Постройте углы ADN и NDB, если ÐADN = 34°, ÐNDB = 120°. Какой может быть градусная мера угла ADB ?

Answer 1

Calculations:

To calculate the given expressions, let's break them down step by step:

1. 2.66 : 3.8 - 0.81 × 0.12 + 0.0372: - First, perform the multiplication: 0.81 × 0.12 = 0.0972. - Then, perform the division: 2.66 : 3.8 = 0.7. - Finally, perform the addition and subtraction: 0.7 - 0.0972 + 0.0372 = 0.639.

2. 7.8 × 0.26 - 2.32 : 2.9 + 0.672: - First, perform the division: 2.32 : 2.9 = 0.8. - Then, perform the multiplication: 7.8 × 0.26 = 2.028. - Finally, perform the addition and subtraction: 2.028 - 0.8 + 0.672 = 1.9.

3. In a store, there are 240 kg of fruits. 65% of the fruits were sold. How many kilograms of fruits are left?: - To find the amount of fruits left, we need to subtract the amount sold from the total amount. - 65% of 240 kg is 0.65 × 240 = 156 kg. - Therefore, there are 240 kg - 156 kg = 84 kg of fruits left.

4. In a tanker, there are 850 liters of milk. 48% of the milk was poured into bottles. How much milk is left in the tanker?: - To find the amount of milk left, we need to subtract the amount poured into bottles from the total amount. - 48% of 850 liters is 0.48 × 850 = 408 liters. - Therefore, there are 850 liters - 408 liters = 442 liters of milk left in the tanker.

5. Find the height of a rectangular parallelepiped with a volume of 25.2 dm³, a length of 3.5 dm, and a width of 16 cm: - To find the height, we can use the formula for the volume of a rectangular parallelepiped: Volume = Length × Width × Height. - Converting the width from cm to dm: 16 cm = 0.16 dm. - Plugging the values into the formula: 25.2 dm³ = 3.5 dm × 0.16 dm × Height. - Solving for the height: Height = 25.2 dm³ / (3.5 dm × 0.16 dm) ≈ 4.5 dm.

6. Find the unknown variable: 2.3u + 31 = 2.5u = 67. 13 + 3.2x + 0.4x = 40: - For the first equation, we have 2.3u + 31 = 2.5u + 67. - Subtracting 2.3u from both sides: 31 = 0.2u + 67. - Subtracting 67 from both sides: -36 = 0.2u. - Dividing both sides by 0.2: u = -36 / 0.2 = -180. - For the second equation, we have 13 + 3.2x + 0.4x = 40. - Combining like terms: 3.6x + 13 = 40. - Subtracting 13 from both sides: 3.6x = 27. - Dividing both sides by 3.6: x = 27 / 3.6 = 7.5.

7. Construct angles MOK and KOS, given that ∠MOK = 110° and ∠KOS = 46°. What could be the measure of angle SOM?: - To construct angles MOK and KOS, we start by drawing a line segment MO. - From point O, we draw a ray that forms an angle of 110° with MO. This is angle MOK. - From point O, we draw another ray that forms an angle of 46° with MO. This is angle KOS. - Angle SOM is formed by the intersection of angles MOK and KOS. - The measure of angle SOM can be found by subtracting the measures of angles MOK and KOS from 180°: 180° - 110° - 46° = 24°.

8. Construct angles ADN and NDB, given that ∠ADN = 34° and ∠NDB = 120°. What could be the measure of angle ADB?: - To construct angles ADN and NDB, we start by drawing a line segment AB. - From point A, we draw a ray that forms an angle of 34° with AB. This is angle ADN. - From point B, we draw another ray that forms an angle of 120° with AB. This is angle NDB. - Angle ADB is formed by the intersection of angles ADN and NDB. - The measure of angle ADB can be found by subtracting the measures of angles ADN and NDB from 180°: 180° - 34° - 120° = 26°.

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