A rectangle has a width of 10cm. The rectangle length is 4 times its width

P = 100 centimeters (assuming you are asking for the perimeter)

Step-by-step explanation:

P = 2 (L + W) OR P =  2L + 2W where P equals the perimeter, L equals the length, and W equals the width.

Since the rectangle's length is 4 times its width and given we know the width is 10 centimeters, then the length is 40 centimeters. Now we can substitute these values in our formula, okay?  

P = 2 (L + W)  

P = 2 (40 + 10)  

P = 80 + 20  

P = 100 centimeters

solution:

→c= a b , that is product of a and b is possible only when when a is m × n matrix and b is n × p matrix.

that is, number of columns of a= number of rows of b.

so, size of matrix , c= a b is , if a = (m × n)matrix

b= (n × p)matrix

then a b = [ (m × n)matrix] ×[   (n × p)matrix ]

→→c= a b= [m × p ] matrix

→→size of product a b will be equal to = number of rows of a × number of columns of b