# Area of shape + percentages - math problems

#### Number of problems found: 67

• Pipeline
How much percent has changed (reduced) area of pipe cross-section, if circular shape changed to square with same perimeter?
• Screens
The area of a 25 inch TV screen is 300 inch² the area of a 40 inch TV screen is 768 inch². The area of the smaller screen is what percent of the area of the larger screen?
• Content area and percents
Determine what percentage is smaller cube surface, when the surface area of the wall decreases by 25%.
• Folding table
The folding kitchen table has a rectangular shape with an area of 168dm2 (side and is 14 dm long). If necessary, it can be enlarged by sliding two semi-circular plates (at sides b). How much percent will the table area increase? The result round to one-hu
• The roof
The roof has the shape of a spherical canopy with a base diameter of 8 m and a height of 2 m, calculate the area of the foil with which the roof is covered, when we calculate 13% for waste and residues.
• The room
The room has a cuboid shape with dimensions: length 50m and width 60dm and height 300cm. Calculate how much this room will cost paint (a floor is not painted) if the window and door area is 15% of the total area and 1m2 cost 15 euro.
• Percent change
If the length of a rectangle is increased by 25% and the width is decreased by 10%, the area of the rectangle is larger than the area of the original rectangle by what percent?
• Tiles
The pupils of the building school have to calculate how many roof tiles they will need to cover the roof of the house in the shape of two rectangles measuring 10 x 7.2 m. One roof tile covers a rectangular area of 22 cmx32 cm. How many tiles will they nee
• Waste
How many percents are waste from a circular plate with a radius of 1 m from which we cut a square with the highest area?
• Rectangle area
The length of a rectangle of x units is increased by 10%, and its width of y units is increased by 15%. What is the ratio of the area of the old rectangle to the area of the new rectangle?
• Equilateral triangle vs circle
Find the area of an equilateral triangle inscribed in a circle of radius r = 9 cm. What percentage of the circle area does it occupy?
• Three shapes
1/5 of a circle is shaded. The ratio of area if square to the sum of area of rectangle and that of the circle is 1:2. 60% of the square is shaded and 1/3 of the rectangle is shaded. What is the ratio of the area of circle to that of the rectangle?
• Expansion
If one side of the rectangle is larger 4-times and second 2-times, what percentage increases the area of rectangle?
• Square
If we increase side of the square, increase its area of 63%. What is the percentage we increase side of the square?
• A screen
A screen is 1680 x 1050 pixels. What are the coordinates (and size in pixels) of an centered area which is exactly 33% of the screen size?
• Painting
The room is long 50 meters and wide 60dm and 300 cm high. Calculate how much it will cost painting if area of windows and doors is 15% of the total area. One square meter cost 50cents.
• Triangle KLB
It is given equilateral triangle ABC. From point L which is the midpoint of the side BC of the triangle it is drwn perpendicular to the side AB. Intersection of perpendicular and the side AB is point K. How many % of the area of the triangle ABC is area o
• Hop-garden
The length of the rectangular hop garden Mr. Smith increased by 25% and its width by 30%. What is the percentage change in area of hop garden?
• Metal sheet
How much m ^ 2 of sheet metal is needed to beat a box in the shape of a cube with an edge length of 50 cm, if we add 20% on the folds of the lid and walls?
• Church roof
The roof of the church tower has the shape of a regular tetrahedral pyramid with base edge length 5.4 meters and a height 5 m. It was found that needs to be corrected 27% covering of the roof area. What amount of material will be required?

Do you have an interesting mathematical word problem that you can't solve it? Submit a math problem, and we can try to solve it.

We will send a solution to your e-mail address. Solved examples are also published here. Please enter the e-mail correctly and check whether you don't have a full mailbox.

Please do not submit problems from current active competitions such as Mathematical Olympiad, correspondence seminars etc...

Our percentage calculator will help you quickly calculate various typical tasks with percentages. Examples of area of plane shapes. Percentages Problems.