2) write the quotient of each number by the number before & notice the value:
49/70= 0.7 34.3/49 = 0.7 24.01/34.3 =0.7 16.0807/24.01 = 0.67 ≈0.7 You notice this is a geometric progression with r 0.7 The last term in a GP =ar^(n-1) a=70; r= 0.7 n-1= number of terms (days -1) For last term = 1 ==> then 1=70(0.7)^(n-1) 1/70 = (0.7)^(n-1) log(1/70) =log[(0.7)^(n-1) ==> log1 - log 70 = (n-1) log(0.7) & you will find that it need 11.92 days to equal on & to be less than it will necessitate 12 Days
168cm2 Let r cm be the radius of the balloon, then <span>2pi(r)=23=>r=23/(2pi) </span> <span>The surface area= </span> <span>4pi(r^2)= </span> <span>4pi[23/2pi)]^2= </span> <span>(23^2)/pi=168.386 cm^2 </span> <span>approximately.</span>