# Examples for 8th grade - page 45

- Two circles

Two circles with a radius 4 cm and 3 cm have a center distance 0.5cm. How many common points have these circles? - Circle sector

Circular sector with a central angle 10 ° has area 254 cm^{2.}Calculate its radius r. - 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? - Tiler

On what surface m^{2}tiler must lay 30 square tiles, each of which has a side 25 cm? - Triangle angles

In a triangle ABC the interior angle at the vertex C is twice as the internal angle at the point A. Outer angle at the point B measured 117 degrees. How big is the outer angle at the vertex A? - Greenhouse

Garden plastic greenhouse is shaped half cylinder with a diameter of 6 m and base length 20 m. At least how many m^{2}of plastic is need to its cover? - Isosceles trapezoid

The lengths of the bases of the isosceles trapezoid are in the ratio 5:3, the arms have a length of 5 cm and height = 4.8 cm. Calculate the circumference and area of a trapezoid. - Seamstress

Seamstress bought two kinds of textile together 25 meters. One at 50 SKK and the second 70 SKK per meter. How many meter bought from this two textiles when paid totally 1540 SKK? - Median

In triangle ABC is given side a=10 cm and median ta= 13 cm and angle gamma 90°. Calculate length of the median tb. - Pair

They have together 48 years - he has 2 times as she was when he was equal as she has today .... - Obtuse angle

The line OH is the height of the triangle DOM, line MN is the bisector of angle DMO. obtuse angle between the lines MN and OH is four times larger than the angle DMN. What size is the angle DMO? (see attached image) - QuizQ2

The square of the first number is equal to three-fifths of the second number. Determine both numbers if you know that the second number is 5 times greater than the first, and neither of numbers is not equal to zero. - Snowman

In a circle with a diameter 41 cm are drawn 3 circles /as a snowman/ where: its diameters are integers, each larger circle diameter is 3 cm larger than the diameter of the previous circle. Determine snowman height if we wish highest snowman. - Motor physics

Car traveling at 97 km/h on the highway. Pulling power of the motor is 6 kN. Determine engine power in kW. - Rhombus

Calculate the length of the diagonal AC of the rhombus ABCD, if its perimeter is 352 dm and the other diagonal BD has length 148 dm. - Unions

Calculate how much money per year would go to the treasury of unions if 447 thousand employee join unions with an average net salary of 539 euros and if memberhip in union cost 1% of the net monthly salary. - Base

Base of building is circle with diameter 39 m. Calculate the circumference of a circular trench witch diameter is 21 cm wider than the diameter of the base. - Cu wire

Copper wire has a length l = 210 m and diameter d = 10 mm. Calculate the weight if density of copper is ρ = 8500 kg/m^{3.}Result round to one decimal place. - Square Number

If to a square of integer number add 49, we get the square of next integer number. What is the original number? - Mean

if the mean of the set of data 10, 13, 8, 18, 20, 17, 19, 3, 10, 8, 8, 3, 12, 15, 14, 4, 20, 19, x is 24.36, what is the value of x?

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