Maths practice for 14 year olds - page 279 of 314
Number of problems found: 6263
- Earth's surface
The greater part of the Earth's surface (r = 6371 km) is covered by oceans; their area is approximately 71% of the Earth's surface. What is the approximate area of the land?
- The hall
The hall had a rectangular ground plan, one dimension 20 m longer than the other. After rebuilding, the length of the hall declined by 5 m, and the width increased by 10 m. The floor area increased by 300 m². What were the original dimensions of the hall?
- Chord 2
Point A has a distance of 13 cm from the circle's center with a radius r = 5 cm. Calculate the length of the chord connecting the points T1 and T2 of contact of tangents led from point A to the circle.
- Circular flowerbed
We split the circular flowerbed with a diameter 8 m by concentric circles to circles and annulus with the same area. Find the radius of the circle.
- Parcel
The parcel is rectangular, a trapezoid with bases of 12 m and 10 m and a height of 8 m. On the parcel was a built object with a footprint of an isosceles triangle, with a side of 4 m and a height of three-quarters of a meter. What is the area of the unbui
- Distance runner
Distance runners have already climbed three-fifths of the total route. Thus passed 90 km. How many km does he have to stop? How long is his route?
- Farm2
The farm bred turkeys, geese, hens, and chickens. Everything is 400. Turkeys and geese a hen are 150. No hen has more than one chicken, but some hens have no chick. Half of them are also a quarter of the chickens. When the turkey was subtracted by 15, we
- Trapezoid v3
The isosceles trapezoid has an angle at the first base 40 degrees less than the angle at the second base. How large angles has this trapezoid?
- Holiday SMS
Kucera and Malek start the holiday together. They agreed that they would send an SMS if they were 100 km apart. Kucera traveling at 60 km/h., Malek 90 km/h. They started at 14 hours PM. At what time do they send a message?
- Right trapezoid
The right trapezoid has bases 3.2 cm and 62 mm long. The shorter leg has a length of 0.25 dm. Calculate the lengths of the diagonals and the second leg.
- Field with vegetables
The field planted with vegetables has a rectangular isosceles triangle with a leg length of 24 m. At the triangle's vertices are rotating sprinklers with a range of 12 m. How much of the field sprinkler isn't irrigated?
- Mom and daughter
The mother is 39 years old, and her daughter is 15. Will the mother be four times older than the daughter for many years?
- Hockey match
The hockey match ended with a result of 3:1. How many different storylines may the match have?
- Drunk and alcohol
One drunk measured 2.7 ‰ of alcohol in the blood, another 1.75 ‰. How many grams of alcohol in the blood do they have if they had 6 kg of blood?
- Swing
A child weighing 12 kg is sitting on a swing at 130 cm from the rotation axis. How far away from the rotation (center) axis must he sit down? His mother weighs 57 kg if she wants to be swung in balance.
- Iron fence
One field of iron fence consists of 20 iron rods with a square cross-section of 1.5 cm side and a long 1 meter. How much weight does a field have if the density of iron is 7800 kg/m³?
- Perimeter and legs
Determine the perimeter of a right triangle if the length of one leg is 75%, the length of the second leg, and its area is 24 cm².
- Dining room
The dining room has 11 tables (six and eight seats). In total, there are 78 seats in the dining room. How many are six-and eight-seat tables?
- Chemical parison
The blown parison (with the shape of a sphere) has a volume of 1.5 liters. What is its surface?
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