Question

a rectangle has a width of 20 inch and a diagonal of 29 inch find the length of the rectangle​

Answer 1

Answer 21 inches

Pythagoras theorem: a^2+b^2=c^2

a here is width. b is length and diagonal is c.

a2+b2=c2

20^2+b^2=29^2

400+b^2=841

b^2=841-400

b^2=441

b=sq root of 441.

b=21

Answer 2

The length of the rectangle is​ 21 inch

Step-by-step explanation:

• Given data

        Width of rectangle (B) = 20 inch

        Diagonal of rectangle (D) = 29 inch

        Length of rectangle = L = unknown

• There are right angle triangle formed by length , width and diagonal of rectangle. In this right angle triangle hypotenuse is diagonal of rectangle.

• Then relation between diagonal , length and width of rectangle is given below

        $\mathbf{D^{2}=L^{2}+B^{2}}$

        So

        $\mathbf{L^{2}=D^{2}-B^{2}}$

• We can also write above equation like this

        $\mathbf{L^{2}=(D+B)(D-B)}$

        $\mathbf{L^{2}=(29+20)(29-20)}$

        $\mathbf{L^{2}=49\times 9}$

        $\mathbf{L^{2}=7^{2}\times 3^{2}}$

        On solving

         L =21 inch= This is length of rectangle.