CPhill

The radius = √(29)

So......

Circumference = 2*pi*r  =   2 * 3.14 * √(29)   ≈ 33.8

35/56 = .625 = 62.5%

Remember, to convert a decimal to a percent, move the decimal two places to the right and write a "%" sign.

Take the log of both sides. We have

log 10^-y = log .5   And by a property of logs, we have

-y log 10 = log .5     And log 10 = 1    So we have

-y = log .5

-y = -.301

So  y = .301

Sorry....Anonymous is correct......I forgot that we were finding a sum !!  My bad !!

Thumbs down for me, and Thumbs up for Anonymous.....

So we have something like this :

Let's use the Law of Cosines to confirm that the length of AC is correct. So we have:

$${\left({{\mathtt{6.4}}}^{{\mathtt{2}}}{\mathtt{\,\small\textbf+\,}}{{\mathtt{4.2}}}^{{\mathtt{2}}}{\mathtt{\,-\,}}{\mathtt{2}}{\mathtt{\,\times\,}}\left({\mathtt{6.4}}{\mathtt{\,\times\,}}{\mathtt{4.2}}\right){\mathtt{\,\times\,}}\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{cos}}{\left({\mathtt{138}}^\circ\right)}\right)}^{{\mathtt{0.5}}} = {\mathtt{9.927\: \!309\: \!092\: \!480\: \!374\: \!7}}$$

And to the nearest tenth, we have 9.9 inches

Thumbs UP from me, GoldenLeaf !!

I believe you have a geometric series here, and you would like to find the 15th term ??

The terms of the series are given by 4*3^(n-1)

so, we have 4*3^(15-1) = 4*3⁽¹⁴⁾ = 19,131,876

Just cross-multiply.......3x8 = 24x1 ......and that is true...thus, these are proportional.

Let L = 4W

Then 2(4W) + 2W = 80

Then 10W = 80   and W = 8

And L = 4(8) = 32.