Expression of a variable from formula - examples - page 18

  1. Boys and girls
    children_16 There are 28 girls in the hall. 5/7 of all children are boys. How many children and how many boys are there?
  2. Trapezium
    trapezium_1 The area of trapezium is 35 cm2. Find its altitude if the bases are 6cm and 8 cm.
  3. Circle chord
    circles_6 Calculate the length of the chord of the circle with radius r = 10 cm, length of which is equal to the distance from the center of the circle.
  4. The rope
    rhombus-diagonals_2 A 68 centimetre long rope is used to make a rhombus on the ground. The distance between a pair of opposite side corners is 16 centimetres what is the distance between the other two corners?
  5. Third member
    seq_6 Determine the third member of the AP if a4=93, d=7.5.
  6. Alley
    stromy_6 Alley measured a meters. At the beginning and end are planted poplar. How many we must plant poplars to get the distance between the poplars 15 meters?
  7. Solve equation
    hrusky_2 solve equation: ?
  8. Hexagon cut pyramid
    truncated_hexa_pyramid Calculate the volume of a regular 6-sided cut pyramid if the bottom edge is 30 cm, the top edge us 12 cm, and the side edge length is 41 cm.
  9. Right triangle from axes
    axes2 A line segment has its ends on the coordinate axes and forms with them a triangle of area equal to 36 sq. Units . The segment passes through the point ( 5,2). What is the slope of the line segment. ?
  10. Free fall
    volny pad How long does the stone fall freely into a depth of 80m? What speed will it hit the bottom of the abyss?
  11. Diagonal
    trapezium_right_1 he rectangular ABCD trapeze, whose AD arm is perpendicular to the AB and CD bases, has area 15cm square. Bases have lengths AB = 6cm, CD = 4cm. Calculate the length of the AC diagonal.
  12. Unknown number 17
    5to2 Milada said, I am thinking of a number such that I evaluate expression x1/3, the value of the expression would be 5. Which number Milada thinking?
  13. Area of iso-trap
    diagons-of-an-isosceles-trapezoid Find the area of an isosceles trapezoid, if the lengths of its bases are 16 cm, and 30 cm, and the diagonals are perpendicular to each other.
  14. Circle - AG
    circle2 Find the coordinates of circle and its diameter if its equation is: ?
  15. Three painters
    workers_37 The three painters have painted bridge. The first would work done in 5 days, the second in 6 days, and the third in 7.5 days. How long will the bridge work if they work together?
  16. Trapezoid - intersection of diagonals
    intersect_trapezoid_diagonals In the ABCD trapezoid is AB = 8 cm long, trapezium height 6 cm, and distance of diagonals intersection from AB is 4 cm. Calculate trapezoid area.
  17. Equation of circle
    circle_analytics find an equation of the circle with indicated properties: a. center at (-3,5), diameter 20. b. center at origin and diameter 16.
  18. Surface of cubes
    cubes3_6 Peter molded a cuboid 2 cm, 4cm, 9cm of plasticine. Then the plasticine split into two parts in a ratio 1:8. From each part made a cube. In what ratio are the surfaces of these cubes?
  19. Equation of circle 2
    circle_axes Find the equation of a circle which touches the axis of y at a distance 4 from the origin and cuts off an intercept of length 6 on the axis x.
  20. Simplify
    numbers3_1 Simplify the following problem and express as a decimal: 5.68-[5-(2.69+5.65-3.89) /0.5]

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