Examples for 9th grade - page 47

  1. Count of triangles
    SquareTriangle Given a square ABCD and on each side 8 internal points. Determine the number of triangles with vertices at these points.
  2. Cube 7
    krychle_4 Calculate the volume of a cube, whose sum of the lengths of all edges is 276 cm.
  3. Rectangle - sides 3
    stvorec If in the rectangle ABCD we enlarge the side a by 5 cm and decrease the side b by 2 cm, the rectangle area will be reduced by 5 cm². When we decrease the length of the side a by 4 cm and and at the same time we increase the length of side b by 3 cm we incr
  4. Three siblings
    brothers Three siblings have birthday in one day-today. Together they have 35 years today. The youngest is three years younger than middle and the oldest is 5 years older than middle. How old is each?
  5. Sportsman
    lungs A trained athlete is able to exhale after a deep breath still 500 ml of air. At normal inhalation and exhalation is breathing 500 ml of air. Within one minute, one breath and exhaled 14 times. What part of breathing air per day is one exhalation?
  6. Angles of a triangle
    triangles_9 In the triangle ABC, the angle beta is 15° greater than the angle alpha. The remaining angle is 30° greater than the sum of the angles alpha and beta. Calculate the angles of a triangle.
  7. Quadrant
    quadrants In what quadrant is a -1165° angle?
  8. Freight train
    Freight_train The train carries 525 tons of limestone in 29 wagons. Wagons are 15 tonne and 20 tons. How many is 15 ton and how many is 20 ton wagons?
  9. Smallest internal angle
    angles_3 Calculate what size has the smallest internal angle of the triangle if values of angles α:β:γ = 3:4:8
  10. Hexa prism
    hexagon Determine the volume of hex prism with edge base 4 cm. The body height is 28 cm.
  11. The farmer
    kombajn The farmer harvested 840 tons of grain in 2006, which was 44% less than in 2005, and one-fifth more than in 2004. How many tons of grain harvested in years 2005 and 2004?
  12. Two numbers
    third The sum of two numbers is 1. Identify this two numbers if you know that the half of first is equal to the third of second number.
  13. Product
    floring The product of two consecutive odd numbers is 8463. What are this numbers?
  14. Pine
    trees How much of a mixed forest rangers want to cut down, if their head said: "We only cut down pine trees, which in our mixed forest 98%. After cut pine trees constitute 94% of all trees left."
  15. Pyramid in cube
    pyramid_in_cube In a cube with edge 12 dm long we have inscribed pyramid with the apex at the center of the upper wall of the cube. Calculate the volume and surface area of the pyramid.
  16. Line segment
    line-segment.JPG For the line segment whose endpoints are L[-10, -14] and M[-13, -4], find the x and y value for the point located 3 over 4 the distance from L to M.
  17. Holidays
    ndr Of the 35 students of class were 7 on holiday in Germany and just as much in Italy. 5 students visited Austria. In none of these countries was 21 students, all three visited by one student . In Italy and Austria were 2 students and in Austria and Germany.
  18. Passenger car and truck
    2cars From Kutna Hora left at 11:00 clock a truck at 60 km/h. At 12:30 behind him started passenger car at average speed 80 km/h. At what time and how far from Kutna Hora overtake a passenger car truck?
  19. Cuboid - volume and areas
    cuboid_10 The cuboid has a volume of 250 cm3, a surface of 250 cm2 and one side 5 cm long. How do I calculate the remaining sides?
  20. Mean
    integrales if the mean of the set of data 5, 17, 19, 14, 15, 17, 7, 11, 16, 19, 5, 5, 10, 8, 13, 14, 4, 2, 17, 11, x is -91.74, what is the value of x?

Do you have interesting mathematical example that you can't solve it? Enter it and we can try to solve it.

To this e-mail address we will reply solution; solved examples are also published here. Please enter e-mail correctly and check whether you don't have a full mailbox.