<span>60.5 milligrams per square centimeter
First, determine how many half lives have expired by dividing the time by the half-life. So:
55/20 = 2.75
That means that only 2^(-2.75) = 0.148650889 = 14.8650889% of the original substance remains. So just divide the amount remaining by 0.148650889 to get the original amount.
9 / 0.148650889 = 60.5445419
So originally, there was 60.5 milligrams per square centimeter 55 years ago.</span>
Answer:
<em>a = </em>60°
<em>b </em>=<em> </em>120°
Step-by-step explanation:
First, you can find measure <em>a </em>by using the first shape. There are six rhombuses, and you can use the innermost <em>a </em>of each one to form a circle. A full circle is 360°, so divide 360 by six. The answer is sixty. So on the next shape, the <em>a</em> measurements add up to 120°. Subtract that from the circle: 360 - 120 = 240. And since there are two measurements for <em>b</em>, you would divide 240 by two. The answer is 120.
To check your work, use the knowledge that circles are 360° (the four interior corners of a rhombus will also add up to 360°. 2(120) + 2(60) = 360. Hope this helps! Feel free to ask any questions!
9514 1404 393
Answer:
4
Step-by-step explanation:
The distributive property does not appear to be involved in this question.
Let n represent the number of Noah's pencils. Then Andrew's total is ...
3n +5 = 17
3n = 12 . . . . . subtract 5 from both sides
n = 4 . . . . . . divide both sides by 3
Noah has 4 pencils.
17 pencils. I’m preety sure
2*5 = 10
2*2 = 4
4(10) + 2(4) = 40 + 8 = 48
ans) 48cm
