Let bold upper a equals start 3 by 3 matrix 1st row 1st column 1 2nd column negative 2 3rd column negative 2 2nd row 1st column 10 2nd column negative 3 3rd column 1 3rd row 1st column negative 10 2nd column 5 3rd column 1 endmatrix comma bold upper b equals start 3 by 3 matrix 1st row 1st column 9 2nd column 4 3rd column negative 4 2nd row 1st column 4 2nd column 7 3rd column 0 3rd row 1st column negative 4 2nd column 0 3rd column 11 endmatrix period find left-parenthesis bold upper a plus bold upper b right-parenthesis superscript 2.

Answer: d. 39 cmin the diagram, the approximate length of the minor arc de is 39 centimetres.step-by-step explanation: the formula for the length of an arc in a circle is as displayed below.let the length of the minor arc de = xx = 2( pi )r × angle of sector / 360°from this, we will substitute the values given from the problem into the formula to obtain the length of the minor arc de.x = 2( pi )r × angle of sector / 360°r = radius = 25cmpi as an approximate value = 3.14angle of sector = 120°x = 2( 3.14 )( 25 ) × 120° / 360°x = 157 × 1 / 4x = 39.25x = 39 ( rounded to the nearest whole number as an approximate value )