# Examples for 8th grade

- Is right-angled

Can a triangle with the sides of sqrt 3, sqrt 5 and sqrt 8 (√3, √5 a √8) be a right triangle? - Isosceles

Isosceles trapezium ABCD ABC = 12 angle ABC = 40 ° b=6. Calculate the circumference and area. - Two chords

There is a given circle k (center S, radius r). From point A which lies on circle k are starting two chords of length r. What angle does chords make? Draw and measure. - Sweater

Dana confuses sweater and wool has a choice of seven colors. In how many ways she can choose from three colors to the sleeves? - Double ladder

The double ladder is 8.5m long. It is built so that its lower ends are 3.5 meters apart. How high does the upper end of the ladder reach? - Cube into sphere

The cube has brushed a sphere as large as possible. Determine how much percent was the waste. - Digit sum

How many are three-digit numbers that have a digit sum of 6? - Right triangle

Calculate the length of the remaining two sides and the angles in the rectangular triangle ABC if a = 10 cm, angle alpha = 18°40'. - Two rectangles

I cut out two rectangles with 54 cm², 90 cm². Their sides are expressed in whole centimeters. If I put these rectangles together I get a rectangle with an area of 144 cm^{2.}What dimensions can this large rectangle have? Write all options. Explain your calcu - CuSO4 mixture

How many grams of solid CuSO4 we have to add to 450g of 15% CuSO4 solution to produce a 25% solution? - The big clock

The big clock hands stopped at a random moment. What is the probability that: a) a small hand showed the time between 1:00 and 3:00? b) the big hand was in the same area as a small hand in the role of a)? c) did the hours just show the time between 21:00. - 5 people

5 people have $122000 and 1 person has $539000 How much should each person (equally) pay? - Performance

Two masons with the same performance would have made of plaster for 6 days. One of them, however, has increased its daily performance by 50%. How long would take they now to make plaster together? - Bulbs

There are 875 identical light bulbs in the sports hall lightning for 2 hours. How long does it lightning 100 this light bulbs? - 40% volume

40% volume with 104 uph (units per labor hour) 8 people working. What is the volume? - Scientific notation

Approximately 7.5x10^{5}gallons of water flow over a waterfall each second. There are 8.6x10^{4}seconds in 1 day. Select the approximate number of gallons of water that flow over the waterfall in 1 day. - Equilateral cylinder

A sphere is inserted into the rotating equilateral cylinder (touching the bases and the shell). Prove that the cylinder has both a volume and a surface half larger than an inscribed sphere. - An oil

An oil drum is cut in half. One half is used as a water trough. Use the dimensions; length 82cm, width 56cm to estimate the capacity of the water trough in liters. - Resistance

A resistor having an electrical resistance of 1.5 k ohms passes an electrical current of 0.1 A. Calculate what voltage is between the terminals of the resistor. - Triangles

Five sticks with a length of 2,3,4,5,6 cm. How many ways can you choose three sticks to form three sides of a triangle?

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