please can someone explain to me how this is done the answer is 85 but how to figure it out I am giving away 10 points the question is one the image and the answer is 85 but just explain how it is done

Step-by-step explanation:

A =

h = 10 cm , b = 17 cm

A = 10 × 17 ÷ 2 = 85 cm²

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

practice. practice. practice.