$54/$89 means she has dared 60.6742% or you can round to 60.67%
Answer:
2676 yards
Step-by-step explanation:
12*223 is 2676
if each costume requires 223 yards then all you do is multiply the numbers
Think of it this way: Lets add numbers in pairs, starting at the very outer 2 numbers (19 and 77) then go in by one and add the second number and the second to last (20 and 76), then (21 and 75) and so on. The sum of all of these pairs are all the same: 96. How many 96s will we have? Well since we're coming from each end toward the middle adding pairs we will have half the distance between 19 and 77, that is (77-19)/2 = 29. So we can actually just take 96*29 = 2784. This is the sum of all numbers between 19 and 77
Use the property
(a -b)(a+ b) = a^2 - b^2
49x^2 - 81 = (7x + 9)((7x - 9)
