# Examples for 9th grade - page 15

- Heron backlaw

Calculate missing side in a triangle with sides 33 and 27 and area 118.3. - Pairs

At the table sit 12 people, 6 on one side and 6 on the other side. Among them are 5 pairs. Every pair wants to sit opposite each other. How many ways can they sit? - EQL triangle

Calculate inradius and circumradius of equilateral triangle with side a=100 cm. - Morse alphabet

Calculate how many words of Morse code to create compiling commas and dots in the words of one to five characters. - Wheat

The rectangle shaped field with dimensions 979 m and 540 m harvested last year was 2775 q wheat. (1 q = 1 quintal = 100 kg). During the year, it was necessary to fix the pipe and therefore did kick wide 6 m parallel to the side of the field 540 m, where no - Compass

What angle are between directions W (West) and SE (SouthEast) on the compass? - Steamship

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? - Scrap

From 8 products are 2 scrap. What is the probability that the random pick of 2 products have no defective product? - Parallelogram

Calculate area of the parallelogram ABCD as shown if |AB| = 45 cm, |BC| = 23 cm and angle BAD = 30° - Cone and the ratio

Rotational cone has a height 28 cm and the ratio of the base surface to lateral surface is 4: 7. Calculate a surface of the base and the lateral surface. - Blueberries

Marie earns 1.8 liters of blueberries for 1.2 hours, Peter 2.6 liters for 1.2 hours. How long have earns together one liter? - Accidents

The count of accidents in 1993 caused 8009 women which is 7.1%. How many men caused the accidents? - Tea blend

Tea blends are maked from two kinds of tea. In standard tea mixture are two teas in the ratio 1:3 and 40 g costs 42 CZK. In the premium tea mixture are weighing two teas in the ratio 1:1 and 50 grams costs 60 CZK. How much cost 10 grams of more expensive k - Vector

Calculate length of the vector v⃗ = (-2.5, 6.25, -4.25). - Coin and die

Flip a coin and then roll a six-sided die. How many possible combinations are there? - Truncated cone

Calculate the height of the rotating truncated cone with volume V = 1299 cm^{3}and a base radii r_{1}= 6.3 cm and r_{2}= 9.7 cm. - Drunk man

Drunkman has 2.1‰ of alcohol in the blood. How many grams of alcohol has in blood, if he have 6 kg of blood? - Leveling

Calculate how many 25 kg bags of leveling concrete must be purchased if we leveling room 28 m^{2}to the "height" 12 mm if consumtion is 1.7 kg per square meter and millimeter thickness. - Right triangle

Calculate the missing side b and interior angles, perimeter and area of a right triangle if a=10 cm and hypotenuse c = 16 cm. - Three workers

Three workers A, B, C have to work on a specific task. Workers A and B completed whole task in 25 days, B together with C for 16 days, A together with C for 10 days. How long it would take to complete the task every one of them alone? How long it would.

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