Answer:
(a) 320 cm²
(b) 75 cm³
Step-by-step explanation:
The scale factor from A to B is 8/4 = 2.
The scale factor of the areas is 2² = 4.
The scale factor of the volumes is 2³ = 8.
(a)
80 cm² * 4 = 320 cm²
(b)
600 cm / 8 = 75 cm³
Answer:
an = 115 + (n - 1) (-6)
a25 = - 29
Step-by-step explanation:
We use the definition for the nth term of an arithmetic sequence:
an = a1 + (n - 1) d
a5 = 91 = a1 + (5 - 1) d
91 = a1 + 4 d
a20 = 1 = a1 + (20 - 1) d = a1 + 19 d
1 = a1 + 19 d
now we subtract term by term one expression from the other
90 = 4 d - 19 d
90 = - 15 d
divide both sides by -15 to isolate d
d = 90 / (-15) = -6
Now we can calculate what a1 is using for example:
1 = a1 + 19 d
1 = a1 - 114
add 114 to both sides:
115 = a1
Then our general expression for the sequence is:
an = 115 + (n - 1) (-6)
We can now use it to calculate the value of a25:
a25 = 115 + (24) * (-6) = -29
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Answer:
Step-by-step explanation:
$40 - $6 - $2 - $6 = $40 - $14 = $26