Answer:
A=pir²
Step-by-step explanation:
pi=3.14
r=15
r²=15²=225
A=225× 3.14= 706.5
Answer:
9/10
Step-by-step explanation:
2n+3=12n-6
3=12n-2n-6
3=10n-6
10n=3+6
10n=9
n=9/10
Answer && Step-by-step explanation:
Obtain yards by multiplying miles by 1760
== 3520 yards
If you use a laptop: 9.25; a desktop with a CRT monitor: 55.51; a desktop with an LCD monitor: 46.26.
A laptop that is plugged up and turned off uses 0.001kw/hr of energy. Each kwh of energy produces, on average, 1.39 lbs of CO2. There are 24*7=168 hours in the week; subtract the 40 hour work week from this and we have 128 hours a week for 52 weeks a year:
0.001*128*52=6.656*1.39=9.25.
A desktop that is plugged up and turned off uses 0.004kw/hr of energy. A CRT monitor uses 0.002 kw/hr when turned off. This means we have:
(0.004*128*52*1.39)+(0.002*128*52*1.39)=55.51.
For a desktop and an LCD monitor, which uses 0.001 kw/hr of energy, we have:
(0.004*128*52*139)+(0.001*128*52*1.39)=46.26.
The percentage of the radioactive isotope left is 25.0000%.
<h3>What is the half life?</h3>
The half life of a radioactive isotope is the time that will elapse before only half of the number of original isotopes will remain.
Now;
We are told that;
Half life (t1/2) = 55 days
Time taken (t) = 115 days
Ratio of isotope remaining = N/No
Thus;
N/No = (1/2)^t/t1/2
N/No = (1/2)^115/55
N/No = (1/2)^2
N/No =1/4
Hence, the percentage = 1/4 * 100/1 = 25.0000%
Learn more about half life of an isotope:brainly.com/question/16387602
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