Only #6ac please explain.

Step-by-step explanation:

the percentage error: P

Approximate value=a 1.41

Exact = e(1.41421356 or √2)

p=[(e-a)/e]×100

p=[√2-1.41)/√2]×100

p=0.29794385 ≅0.30 or 30 percent when rounded to the nearest hundredth

b: p=[(π-3.14)/π]×100=0.05069573≅0.05 =5 percent when rounded to the nearest hundredth. in the pi case the percentage of error is small 5 % but in the case of square roots the percentage id higher(30%). in this case it is better to round the answer at the end of calculation( math problem)

c) sometimes when rounding square roots or irrational number like pi it is useful to use decimal approximate, in the case of pi the percentage rate was 5 percent which is very low comparing to the square root which is 30 %.

e^-kt = n/n0 = 0.79  

-kt = ln 0.79  

t = - ln 0.79/0.0001  

= 2357 years

step-by-step explanation: