Plz help asap i really need it for 30 points

Mathematics

1 answer:

Pani-rosa [81]3 years ago

6 0

Answer:

13.04 cm^2

Step-by-step explanation:

Larger Circle diameter is 12.5 cm and the smaller is 3.5 cm

The Area of a circle is A = πr^2 = πd^2/4

Larger Circle divide the diameter by 2 = 6.25 cm

Smaller Circle dive the diameter by 2 = 1.75 cm

Using above formula A = 122.71846303085 cm^2 &

Finally we deduct the smaller Area from the larger Area

A = 9.6211275016187 cm^2 - 9.6211275016187 cm^2

122.71846303085 cm^2 - 9.6211275016187 cm^2 =

113.0973355292 cm^2 thus 13.04 is your answer since I used the

π = 3.1415926535898

A = area

π = pi = 3.1415926535898

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Scientist can determine the age of ancient objects by a method called radiocarbon dating. The bombardment of the upper atmospher

Artemon [7]

Answer: 2500 years

Step-by-step explanation:

I'm not quite sure if I'm doing this right myself but I'll give it a shot.

We use this formula to find half-life but we can just plug in the numbers we know to find t.

$A(t)=A_{0}(1/2)^t^/^h$

We know half-life is 5730 years and that the parchment has retained 74% of its Carbon-14. For $A_{0$ let's just assume that there are 100 original atoms of Carbon-14 and for A(t) let's assume there are 74 Carbon-14 atoms AFTER the amount of time has passed. That way, 74% of the C-14 still remains as 74/100 is 74%. Not quite sure how to explain it but I hope you get it. h is the last variable we need to know and it's just the half-life, which has been given to us already, 5730 years, so now we have this.

$74=100(1/2)^t^/^5^7^3^0$

Now, solve. First, divide by 100.

$0.74=(0.5)^t^/^5^7^3^0$

Take the log of everything

$log(0.74)=\frac{t}{5730} log(0.5)$

Divide the entire equation by log (0.5) and multiply the entire equation by 5730 to isolate the t and get

$5730\frac{log(0.74)}{log(0.5)} =t$

Use your calculator to solve that giant mess for t and you'll get that t is roughly 2489.128182 years. Round that to the nearest hundred years, and you'll find the hopefully correct answer is 2500 years.

Really hope that all the equations that I wrote came out good and that that's right, this is definitely the longest answer I've ever written.

5 0

3 years ago

Consider the circle with a radius of 30 cm. What is the approximate circumference of the circle? (use 3.14 as an approximation o

Goshia [24]

Answer: 188.4 cm

Step-by-step explanation:

Given

the radius of the circle is $r=30\ cm$