Answer:
Step-by-step explanation:
Given
Garden: 
One Bag: 
Requires
Determine the number of bags to cover the whole garden
This is calculated as thus;

Expand the numerator



Express 81 as 9²

Evaluate as difference of two squares


Hence, the number of bags is 
Step-by-step explanation:
p = x / n
p = 550 / 1083
p = 0.5078
Answer
(13+4) + (4.63+7.4)
Step-by-step explanation:
Use the commutative property to put the decimals together. Use the associative property to group the decimals and numbers together as shown in the answer.
If you look at the hundereds place you see it is under the number 5 which means you would drop 1, 5, & 9 and the answer would be 105,000. If the number was above 5 you would have had to make it 106,000.
Use the identity cos^2 (a/2) = 1/2 (1 + cos a) so
cos^ 2 22.5 = cos^2 (45/2) = 1/2 ( 1 + cos 45) = 1/2(1 + sqrt2/ 2)4 = 1/2 + sqrt2/4
cos 22.5 = sqrt ( 1/2 + sqrt2/4) Answer