Answer:
15
Step-by-step explanation:
The hypotenuse of a triangle is a² + b² = c².
12² + 9² = c²
144 + 81 = 225
√225 = 15
<span>The center is x = 1, y = -1.
The radius is 2. </span>
A half-life of the isotope is 15 days and at start its mass is 32 g.
A table:
t: m:
0 32 g
15 16 g
30 8 g
45 4 g
60 2 g
75 1 g
In the first column is used an arithmetic sequence ( a 1 = 0, d = 15 ).
In the second column is used a geometric sequence ( a 1 = 32, r = 1/2 )