# Examples for 9th grade - page 12

- Wire

One pull of wire is reduced its diameter by 9%. What will be diameter of wire with diameter 9 mm over 8 pulls? - Estate

Semicircle estate must be fence. The straight section has 44 meters long fence. How many meters of fence should buy? - Octahedron - sum

On each wall of a regular octahedron is written one of the numbers 1, 2, 3, 4, 5, 6, 7 and 8, wherein on different sides are different numbers. For each wall John make the sum of the numbers written of three adjacent walls. Thus got eight sums, which also. - 4side pyramid

Calculate the volume and surface of 4 side regular pyramid whose base edge is 4 cm long. The angle from the plane of the side wall and base plane is 60 degrees. - Canopy

Mr Peter has metal roof cone shape with a height of 36 cm and radius 73 cm over well. He needs paint the roof with anticorrosion. How many kg of color must he buy if the manufacturer specifies the consumption of 1 kg to 2.1 m^{2}? - Square 2

Points D[9,-1] and B[3,3] are opposed vertices of the square ABCD. Calculate area of the square ABCD. - Stairway

What angle rising stairway if step height in 17 cm and width 24 cm? - Prism

Calculate the volume of the rhombic prism. Base of prism is rhombus whose one diagonal is 39 cm and the edge of the base is 24 cm. The edge length of the base of the prism and height is 3:2. - OK circle

Calculate the radius (circumradius) of the circle described right triangle with hypotenuse long 43 and one cathetus long 21. - Climb

Road has climbing 1:23. How big is a angle corresponds to this climbing? - n-gon

Gabo draw n-gon, which angles are consecutive members of an arithmetic sequence. The smallest angle is 70° biggest 170°. How many sides have Gabo's n-gon? - Pyramid a+h

Calculate the volume and surface area of the pyramid on the edge and height a = 26 cm. h = 3 dm. - Two doctors

Doctor A will determine the correct diagnosis with a probability 80% and doctor B with a probability 72%. Calculate probability of correct diagnosis if patient is diagnosed by both doctors. - Rectangles

How many rectangles with area 2832 cm^{2}whose sides is natural numbers are? - Motion

From two different locations distant 104 km started against car and bus. The car started at 5:30 with average speed 58 km/h. Bus started at 6:40 with average speed 79 km/h. When they meet? How many kilometers went the bus? - Rotary cone

Rotary cone whose height is equal to the circumference of the base, has a volume 4772 cm^{3.}Calculate the radius of the base circle and height of the cone. - 2x cone

Circular cone height 60 cm was cut plane parallel with base. Volume of these two small cones is the same. Calculate the height of the smaller cone. - Sale

If the product twice price cut by 20%, what percentage was price cut in total? - Cut and cone

Calculate the volume of the rotation cone which lateral surface is circle arc with radius 14 cm and central angle 114 degrees. - Circle section

Equilateral triangle with side 50 is inscribed circle section whose center is in one of the vertices of the triangle and the arc touches the opposite side. Calculate: a) the length of the arc b) the ratio betewwn the circumference to the circle sector.

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