Element X decays radioactively with a half life of 11 minutes. If there are 180 grams of Element X, how long, to the nearest tenth of a minute, would it take the element to
decay to 17 grams?
y = a(.5)

you estimate that the angle of elevation to the top of the 86th floor (the observatory) is 82 .the total height of the building is another 123 meters above the 86th floor.

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you should go to the second answerthey explain it very well, give me a like

we need to divide the number of toy dinosaurs, 156, by the number of brothers, 4:

in order to estimate, we can use compatible numbers:

156 ÷ 4

  ↓

160   ÷ 4 = 40        

the correct answer is a).