How do u do this? i need in my hw

To write a mixed number such as 8 and 1/4 as a decimal, you convert the fraction (1/4, in this case), and add the converted fraction to the integer (the 8).

1/4 as a decimal is 0.25. Couple ways you can see this: divide 1 by 4 either by hand or with a calculator.
Or 

Now add the converted decimal 0.25 to 8 to get the answer 8.25

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 )