How do you find the indicated length?

You need a formula to find the length OS a line. It is (x1 + x2) / 2 ... (y1 + y2) / 2

Example: (1,3) (5,3) The first number in the parenthesis is x. Add both of them. 1+5=6 then divide it by 2. 6/2=3. The the second set of numbers in te parenthesis is y. Add both of them. 3+3=6. The divide by 2. 6/2=3. Lastly, you add both x and y together. 3+3=6. And now you answer is 6.