The half-life of radium is 1690 years. If 90 grams are present now, how much will be present in 400 years?
1 answer:
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Answer:
The measure of angle N is 55°
Step-by-step explanation:
we know that
the law of cosines established
a² = b² + c² – 2*b*c*cos(A)
so
In this problem we have
a=ML=5.74 units
b=LN=4 units
c=MN=7 units
∠A=∠N=?
see the attached figure to better understand the problem
a² = b² + c² – 2*b*c*cos(A)------> cos (A)=[b²+c²-a²]/[2*b*c]
cos (A)=[4²+7²-5.74²]/[2*4*7]------> 0.57236
A=arc cos (0.57236)--------> A= 55°
therefore
The measure of angle N is 55°
