To model half-life, use the formula

. Here,

is the amount remaining after a length of time

.

is the amount that you start with.

is the half-life. You plug in 50 for

, 10 for

, and 25 for

. You get

.
According to the identity if a+b+c=0
then a3+b3+c3=3abc
a3+b3+c3/abc=3
a2*a/bc*a+b2*b/ca*b+c2*c/ab*c=3
cancel a,b,c in all the fraction then you get
<span>a²/bc+b²/ca+c²/ab=3.
</span>hence proved
Answer:
6.25716517287
Step-by-step explanation:
Area of circle = π × r²
→ 123 = π × r²
⇒ Divide both sides by π
→ 39.1521160006 = r²
⇒ Square root both sides
→ 6.25716517287 = r
.38 is greater because 3/10 is .30 and .38 is greater