The time it takes for 1g of strontium-90 to decay to 250 mg is; 57.6 years
<h3>What is the half life of an element?</h3>
The formula for half life is;
A(t) = A₀ * (¹/₂)^(t/t_1/2)
Where;
A(t) is amount left after t years
A₀ the initial quantity of the substance that will undergo decay;
t_1/2 is the half-life of the decaying quantity.
We are given;
t_1/2 = 28.8 years
A₀ = 1 g
A(t) = 250 mg = 0.25 g
Thus;
0.25 = 1 * (¹/₂)^(t/28.8)
log 0.25 = (t/28.8) log (1/2)
-0.60206 = (t/28.8) * -0.3010
t = 2 * 28.8
t = 57.6 years
Read more about half life at; brainly.com/question/11152793
1) x=9, because we can use the Pythagorean theorem, x^2 + 144 = 225, x^2 = 81
2) 
, because 6^2 +6^2 = 72, 
3) 
, because 
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One skill could be to not<span> rush it—make time for face-to-face contact.</span>
Answer:
What did you do on a typical day.
Explanation:You Wouldn't want to get right in the details of the war because he might not be willing to answer if you ask of the war first.
Give Brainliest Please
Answer:
The agencies being referred in Rachel Carson's <em>"Silent Spring"</em> are the state and federal agencies.
They are being reduced to the "so-called control agencies" because they don't really know much about the <em>effects of chemical insecticides</em> and how <em>potentially dangerous </em>they are to living things, yet they are the ones who allow its distribution to people.<u> They control the insects in the world</u> by allowing spraying operations, however they don't have any idea on how much damage they are causing to the world. Carson reduced this agencies <u>because they were spreading </u><u><em>"misinformation."</em></u>
Explanation:
"Silent Spring" was a book that stirred the public's attention. It talks about the bad effects of using chemical pesticides to the environment. Many critics opposed the book, yet it was able to move the Congress. This resulted to the operation of the Environmental Protection Agency in <em>1970.</em>
