1)

2)

Here, the variable

can assume any value, and usually an inequality presented like this has

as a stand-in for all real numbers. If we really wanted to make that fact clear, we could write the two inequalities like this:

Formally, you'd read

as "

is an element of the set of real numbers," which is a fancy way of saying that

can be any real number.
Answer: how about 90
Step-by-step explanation:
Its a 360 if you multiply 90×4 you get 360 every side is 90 degrees
Answer:
65º
Step-by-step explanation:
- The angle of a straight line is 180º, so ∠ABD=180º and ∠ABC=(180-6x)º
- The sum of the interior angles of a triangle is 180, so (x+40)º+(3x+10)º+(180-6x)º=180
- We can solve from there, x+40+3x+10+180-6x=180
- Combine like terms, -2x+230=180
- Subtract 230, -2x=-50
- Divide by -2, x=25
- m∠CAB=(x+40)º=(25+40)º=65º
- m∠ABC=(180-6x)º=(180-150)º=30º
- m∠BCA=(3x+10)º=(75+10)º=85º
To solve this we are going to use the formula for speed:

where

is the speed

is the distance

is the time
Let

be the speed of the boat in the lake,

the speed of the boat in the river,

the time of the boat in the lake, and

the time of the boat in the river.
We know for our problem that <span>the current of the river is 2 km/hour, so the speed of the boat in the river will be the speed of the boat in the lake minus 2km/hour:
</span>

We also know that in the lake the boat<span> sailed for 1 hour longer than it sailed in the river, so:
</span>

<span>
Now, we can set up our equations.
Speed of the boat traveling in the river:
</span>

But we know that

, so:

equation (1)
Speed of the boat traveling in the lake:

But we know that

, so:

equation (2)
Solving for

in equation (1):


equation (3)
Solving for

in equation (2):




equation (4)
Replacing equation (4) in equation (3):


Solving for

:






or

We can conclude that the speed of the boat traveling in the lake was either
6 km/hour or
5 km/hour.