Answer:
From the level of high tide to low tide, it's 18 feet.
Step-by-step explanation:
To find the change in water level, we multiply the rate (3 ft / hr) by the time (6 hrs), obtaining 18 ft.
The water level changes by 18 ft.

The rows add up to

, respectively. (Notice they're all powers of 2)
The sum of the numbers in row

is

.
The last problem can be solved with the binomial theorem, but I'll assume you don't take that for granted. You can prove this claim by induction. When

,

so the base case holds. Assume the claim holds for

, so that

Use this to show that it holds for

.



Notice that






So you can write the expansion for

as

and since

, you have

and so the claim holds for

, thus proving the claim overall that

Setting

gives

which agrees with the result obtained for part (c).
Answer:
2/15
Step-by-step explanation:
4/5-2/3
12/15-10/15
2/15
The length of DE is 39 and the length of EF is 36 because we can see from side AC and DF that triangle DEF is just triangle ABC dilated by 3.
Answer:
x=110
Step-by-step explanation:
Since the sum of the interior angles of a trapazoid is 360, all you have to do is add the angles given and subtract that by 360, which gets you 110.