Expression of a variable from the formula - practice problems
Work with mathematical expressions. Expressions are mathematical objects where some numbers are replaced by letters - variables. For example, the area of a circle is S = π r2, where r is a variable, the radius of the circle, and S is also a variable, the area. This is how we can describe the relationship between area and radius for all circles, generally. We can modify expressions, simplify, multiply, divide, add, etc. Expressing from a formula means putting some variable on the left side. For example, the radius of a circle r = √ (S/π). For completeness, let us add that the symbol π is a constant, Ludolf's number = 3.14159.... A constant is like a variable, but always with the same value.Number of problems found: 2770
- The surface 5
The surface area of a cylinder is 6140 cm², and the radius is 25 cm. What is the height? - A rope for cow
Find the length of a rope by which a cow must be tethered in order that it may be able to graze an area of 154 sq m . - The average 19
The average age of a class was 15 years. When 5 boys whose average age was 12 years 6 months were admitted in the class, the average was reduced by 6 months. How many students were there in the class originally? - Cu ore
An ore contains 5% copper. How much ore is required to obtain 400 grams of copper?
- The Earth and Moon
The diameter of the Moon is approximately 1/4 of the diameter of the Earth. What fraction of the volume of the Earth is the volume of the Moon? - Salaries - ratio3
The salaries A, B, C are in the ratio 2 : 3 : 5. If the increments of 15%, 10% and 20% are allowed respectively in their salaries, then what will be new ratio of their salaries? - Goods train
A goods train runs at the speed of 72 kmph and crosses a 250 m long platform in 26 seconds. What is the length of the goods train? - Angle of inclination
Find the angle of inclination of a ramp that rise for 80 cm and is 200 cm long. - Tower + pole
On the horizontal plane, there is a vertical tower with a flag pole on its top. At a point 9 m away from the foot if the tower, the angle of elevation of the top and bottom of the flag pole are 60°and 30° respectively. Find the height of the flag pole.
- A rectangle 15
A rectangle is 5 cm longer its width. It areas is 6 cm square. What are the dimensions of the rectangle. - Rhombus = area, diagonal
The area of a rhombus is 144 sq cm. One of its diagonals is twice the other. How long is the shorter diagonal? - The rhombus (a,d) Find the area of a rhombus, one side of which measures 20 cm, and one diagonal 24 cm.
- The length 20
The length and breadth of a rectangular park are in the ratio 8:5. A path,1.5 m wide, running all around the outside of the park has an area of 594 sq m. Find the dimensions of the park. - A field
A field is in the shape of a trapezium whose parallel sides are 25 m and 10 m and the non parallel sides are 14 m and 13 m. Find the area of the field.
- The average 17
The average monthly salary of 20 workers in an office is $4590 . If the manage's salary is added, the average salary becomes $ 4920 per month What's the manager's monthly salary? - Four numbers 3
What least number must be added to each of the numbers 6,15,20 and 43 to make them proportional? - The angle 9
The angle of elevation of the top of a tower from a point A on the ground is 30°. On moving a distance of 20 m towards the foot of the tower to a point B, the angle of elevation increases to 60°. Find the height of the tower and the distance of the tower - Surface = volume
If the volume and the surface area of a sphere are numerically the same then find its radius. - GP - terms
Which term of the G.P., 2, 8, 32, ... up to n terms is 131072?
Triangle made by 6 cm 4.5 cm and 7.5 cm. what angles does it make?Do you have homework that you need help solving? Ask a question, and we will try to solve it. Solving math problems.
