# Expression of a variable from formula - problems

- Cuboid walls

If the areas of three adjacent faces of a cuboid are 8 cm², 18 cm² and 25 cm². Find the volume of the cuboid. - Decagon

Calculate the area and circumference of the regular decagon when its radius of a circle circumscribing is R = 1m - Nonagon

Calculate the area and perimeter of a regular nonagon if its radius of inscribed circle is r = 10cm - Isosceles triangle

The leg of the isosceles triangle is 5 dm, its height is 20 cm longer than the base. Calculate base length z. - The pond

We can see the pond at an angle 65°37'. Its end points are 155 m and 177 m away from the observer. What is the width of the pond? - Square root 2

If the square root of 3m^{2}+22 and -x = 0, and x=7, what is m? - A truck

A truck departs from a distribution center. From there, it goes 20m west, 30m north and 10m west and reaches a shop. How can the truck reach back to the distribution center from the shop (what is the shortest path)? - Sale discount

The product was discounted so that eight products at a new price cost just as five products at an old price. How many percents is the new price lower than the old price? - Expressions 3

If k(x+6)= 4x^{2}+ 20, what is k(10)=? - Find the 5

Find the equation with center at (1,20) which touches the line 8x+5y-19=0 - Population growth

How many people will be on Earth from two people for 5,000 years, if every couple has always 4 children, (2 boys and 2 girls) at the age of 25-35, and every man will live 75 years? - Right triangle from axes

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. ? - A clock

A clock was set right at 6:00 AM. If it gains 3 1/2 minutes per hour, what time will it show at 6:00 PM on the same day? Show your solution - Right Δ

Right triangle has length of one leg 51 cm and length of the hypotenuse 85 cm. Calculate the height of the triangle. - Tereza

The cube has area of base 225 mm^{2.}Calculate the edge length, volume and area of its surface. - MO SK/CZ Z9–I–3

John had the ball that rolled into the pool and it swam in the water. Its highest point was 2 cm above the surface. Diameter of circle that marked the water level on the surface of the ball was 8 cm. Determine the diameter of John ball. - IS trapezoid

Calculate the length of diagonal u and height v of isosceles trapezoid ABCD, whose bases have lengths a = |AB| = 37 cm, c = |CD| = 29 cm and legs b = d = |BC| = |AD| = 28 cm. - Theater

The theater has in each row with 10 seats. Ticket to the first 5 rows is for 21 USD. In next rows is for 13 USD. The theater was completely sold out. Revenue was 3520 USD. How many rows are in the theater? - Floating barrel

Barrel (cylinder shape) floats on water, top of barrel is 8 dm above water and the width of surfaced barrel part is 23 dm. Barrel length is 24 dm. Calculate the volume of the barrel. - Arc and segment

Calculate the length of circular arc l, area of the circular arc S_{1}and area of circular segment S_{2}. Radius of the circle is 33 and corresponding angle is ?.

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