I think it would be B hope it helps
The undefined term that can contain parallel lines are line.
Answer:
We can use the sample about 42 days.
Step-by-step explanation:
Decay Equation:



Integrating both sides


When t=0, N=
= initial amount




.......(1)
.........(2)
Logarithm:
130 days is the half-life of the given radioactive element.
For half life,
,
days.
we plug all values in equation (1)






We need to find the time when the sample remains 80% of its original.







We can use the sample about 42 days.
The area would be 35 cm squared.
Lets break it down:
Triangle- The area of a triangle is base×height÷2
so if we plug in the numbers, the base would be 5 (the length) and the height would be 4 (the height). 5×4= 20÷2= 10.
Square- The area of a square is base×height so if we pluged in the numbers, the base is 5 (the length) and the height is 5 (the height). 5×5= 25.
10+25= 35 cm squared
Hope this helps!