30
I DONT KNOW BUT THAT'S MY ANSWER HOPE IT HELP
I think we're not supposed to do more than 3 problems in one answer; certainly not five pages. Does the 1/3 mean there are 10 more to come?
I'll do the first page.
6)
Right triangle, opposite side of 10, adjacent side of 21,
tan x = opp/adj = 10/21
x = arctan 10/21 = 25.46°
Answer: 25
7)
cos x = adj / hyp = 10/14
x = arccos 10/14 = 44.42°
Answer: 44
8)
tan x = opp/adj = 12/24 = 1/2
x = arctan 1/2 = 26.57°
Answer: 27
9)
tan x = 31/32
x = arctan 31/32 = 44.09°
Answer: 44
10)
x = arctan 10/27 = 20.32°
Answer: 20

In other words, how many ways are there to choose

objects from a total of

objects? Just one; take all of them at the same time.
It would be...
(18 +28) divided by two
then take that and multiply it by the height - 5
the 6 in this equation doesn't matter because it is not the height of the shape
Answer:
80 hours
Step-by-step explanation:
let d represent doug, let l represent laura
first, set up a system of equations representing the problem:
since doug spent 10 less than twice the hours laura did, and we know that the total amount of hours they spent together is 230:
l=2d+10
d+l=230
then solve:
*first i rearranged the equations so i can solve this system of equations using elimination method*
l-2d=10
l+d=230
*subtract*
3d=240
d=80
so, doug spent 80 hours in the lab