Answer:
39 sq cm
Step-by-step explanation:
Ok. Since ΔAED is isosceles, then the height of the trapezoid is 3 cm
One base is 16 and the other base is 16 - 3 - 3 = 10.
A = 1/2 h( +
) where
and
are lengths of the bases
A = 1/2(3)(10 + 16)
= 1/2(3)(26)
= 39 sq cm
9514 1404 393
Answer:
Step-by-step explanation:
The decay factor is 1 -25% = 0.75 per hour, so the exponential equation can be written ...
r(t) = 1450·0.75^t . . . . . milligrams remaining after t hours
__
a) After 4 hours, the amount remaining is ...
r(4) = 1450·0.75^4 ≈ 458.79 . . . mg
About 459 mg will remain after 4 hours.
__
b) To find the time it takes before the amount remaining is less than 5 mg, we need to solve ...
r(t) < 5
1450·0.75^t < 5 . . . . use the function definition
0.75^t < 5/1450 . . . . divide by 1450
t·log(0.75) < log(1/290) . . . . . take logarithms (reduce fraction)
t > log(1/290)/log(0.75) . . . . . divide by the (negative) coefficient of t
t > 19.708
It will take about 20 hours for the amount of the drug remaining to be less than 5 mg.
