Examples for 8th grade - page 57
- The body
The body on the figure consists of cubes with an edge length 10 cm. What surface has this body?
- Family and age ratios
Age of father and son are in the ratio 10:3; age of father and daughter are in the ratio 5:2. How old is father and son, if daughter is 20 years old? In what ratio is age sister and brother?
The perimeter of the parallelogram is 202 cm. The length of one side is 1.2-times longer than the length of the shorter side. What is the length of sides of a parallelogram?
Jarek bought new trousers, but the trousers were too long. Their length was in the ratio 5: 8 to Jarek height. Mother his trousers cut by 4 cm, thus the original ratio decreased by 4%. Determine Jarek's high.
Determine the smallest integer p for which the equation 5 sin x = p has no solution.
- Pedestrian up-down hill
Pedestrian goes for a walk first at plane at 4 km/h, then uphill 3 km/h. Then it is in the middle of the route, turns back and goes downhill at speed 6 km/h. Total walk was 6 hours. How many kilometers went pedestrian?
Pigs are feed by beet.Beet feed containing 12% dry solids, which is 0.66% of digestible crude protein. How much beet must beconsumed in one month (30 days), if the weight of digestible crude protein contained in a daily dose of beet was 0.688 kg?
Above the town hall tower flew the plane with constant speed 508 km/h and 15 minutes later the second plane at speed of 651 km/h. How long and how far from the town hall will be aircrafts caught up?
- Inscribed rectangle
The circle area is 184. Determine the area of inscribed rectangle with one side 10 long.
- ISO trapezium
Calculate area of isosceles trapezoid with base 53 long, leg 43 long and with the angle between the base and leg 70 degrees.
Share of ethnicity XY is 10%, which is 1/9 more than in the prewar period. What was the share of that ethnicity in the pre-war period?
- 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.
- Round table
Round table with diameter d = 95 cm is coated by square tablecloth with a side length 122 cm. About how many cm is higher center of tablecloth than its cornes?
- Similarity coefficient
The ratio of similarity of two equilateral triangles is 3.9 (ie 39:10). The length of the side of smaller triangle is 3 cm. Calculate the perimeter and area of the larger triangle.
Rectangular rink with dimensions of 79.5 m and 529 dm must be covered with a layer of ice 4.5 cm thick. How many liters of water is necessary for the formation of ice when the volume of ice is 10.9% greater than the volume of water.
- n-gon II
What is the side length of the regular 9-gon circumscribed circle of radius 13 cm?
Number 389 divide into the two addends that the first was 6 greater than 60% of the second. Determine these addends.
Right angle prism, whose base is right triangle with leg a = 3 cm and hypotenuse c = 5 cm has same volume as a cube with an edge length of 1 dm. a) Determine the height of the prism b) Calculate the surface of the prism c) What percentage of the cube'
In ▵ ABC, if sin(α)=0.5 and sin(β)=0.1 calculate sin(γ)
Between the two ports on the river is going steamship. The journey there and back takes 14:49. Downstream steamship traveling at 21 km/h, upstream 9 km/h. What is the distance between the ports?