CPhill

We need to know the angle of elevation....!!!!

We have

tan 30 = 10 / apothem  

apothem  = 10 / tan 30  = 17.32cm

Very nice, h7....

Paint needed for one door = 2(2)(.9) = 3.6m^2

So, 20 doors require 20 x 3.6m'2 = 72m^2

So the amount required divided by the amount in each tin gives us....

So.....72m^2 / 8m^2  =  9 tins

Area of floor = 4 x 4.6 = 18.4

Area of each tile = 1 x .2  = .2

Now, eismax13, just divide the first by the second, and that will be your answer...

176 =

88 x 2 =

44 x 2 x 2 =

11 x 4 x 4

So we have

√(11 x 4 x 4) =

4√11  = about 13.27

I can see why, Panda....it is a little sticky!!

First, let's use the Law of Cosines to find angle ABD...so we have

17^2 = 15^2 + 20^2 - 2(15)(20)cosABD

289 = 225 + 400 - 600cosABD

cosABD = [289-225-400] / (-600)

cos-1 (336 / 600) = about 55.9 degrees

And because they are vertical angles, this is the same measure as TBC

And DBC is supplemental = 124.1 degrees

And BCD = (180 - 124.1 - 36) = 19.9 degrees

And we can find BC using the Law of Sines

BC/sin36 = 15/sinBCD

BC/sin36 = 15/sin19.9

BC = 15sin36/sin19.9 = about 25.9

And, because the are vertical angles, ABT = DBC = 124.1 degrees

And ATB = (180 - 41 - 124.1) = 14.9 degrees

And we can find BT using the Law of Sines

BT/sin41 = 20/sinATB

BT/sin41 =20/sin14.9

BT = 20sin41/sin14.9 = about 51

And TBC = ABD = 55.9

And finally, using the Law of Cosines one more time, we can find CT

CT^2 = BT^2 + BC^2 - 2(BT)(BC)cosABD

CT^2 = 51^2 + 25.9^2 - 2(51)(25.9)cos(55.9)

CT = √[51^2 + 25.9^2 - 2(51)(25.9)cos(55.9)]= about 42.32 m

Whew!!!...that one was kinda' tough !!!

-(sinx*tanx) =

-sinx (sinx / cosx) =

-sin^2x / cosx =

[cos^2x - 1 ] / cosx =

1 - secx

The sum of the first N positive intergers is given by

N*(N+1)/2    so we have

100(101)/2 =

50(101) =

5050

If we're plotting points, we move on x, first and then on y.

For instance (3,2) says to start at the origin, move 3 units to the right on the x axis and then 2 units "up"