# Area of a rectangle

Calculate the area of a rectangle with a diagonal of u = 12.5cm and a width of b = 3.5cm. Use the Pythagorean theorem.

Result

S =  42 cm2

#### Solution:

$u = 12.5 \ cm \ \\ b = 3.5 \ cm \ \\ \ \\ a^2 + b^2 = u^2 \ \\ \ \\ a = \sqrt{ u^2-b^2 } = \sqrt{ 12.5^2-3.5^2 } = 12 \ cm \ \\ \ \\ S = a \cdot \ b = 12 \cdot \ 3.5 = 42 = 42 \ cm^2$

Leave us a comment of this math problem and its solution (i.e. if it is still somewhat unclear...):

Be the first to comment!

#### Following knowledge from mathematics are needed to solve this word math problem:

Pythagorean theorem is the base for the right triangle calculator. See also our trigonometric triangle calculator.

## Next similar math problems:

1. Billboard
Rectangular billboard is 2.5 m long with a diagonal 2.8 m long. Calculate the perimeter and the content area of the billboard.
2. Rectangle diagonal
The rectangle, one side of which is 5 cm long, is divided by a 13 cm diagonal into two triangles. Calculate the area of one of these triangles in cm2.
3. The field
The player crossed the field diagonally and walked the length of 250 m. Calculate the length of the field, circumference if one side of field 25 meters.
4. Surveyor
Calculate the area of ​​what may vary rectangular, if it focused by surveyor and found the dimensions 18 x 15 m while in each of the four joint points can be position deviation 25 cm?
5. Rectangle
The rectangle area is 182 dm2, its base is 14 dm. How long is the other side? Calculate its perimeter.
6. Isosceles triangle
Calculate area and perimeter of an isosceles triangle ABC with base AB if a = 6 cm, c = 7 cm.
7. ISO Triangle V2
Perimeter of RR triangle (isosceles) is 474 m and the base is 48 m longer than the arms. Calculate the area of this triangle.
8. Isosceles III
The base of the isosceles triangle is 17 cm area 416 cm2. Calculate the perimeter of this triangle.
9. Median
In the right triangle are sides a=41 dm b=42 dm. Calculate the length of the medians tc to the hypotenuse.
10. Tv screen
The size of a tv screen is given by the length of its diagonal. If the dimension of a tv screen is 16 inches by 14 inches, what is the size of the tv screen?
11. Umbrella
Can umbrella 75 cm long fit into a box of fruit? The box has dimensions of 390 mm and 510 mm.
12. Satin
Sanusha buys a piece of satin 2.4 m wide. The diagonal length of the fabric is 4m. What is the length of the piece of satin?
13. Length IT
Find the length (circumference) of an isosceles trapezoid in which the length of the bases a,c and the height h are given: a = 8 cm c = 2 cm h = 4 cm