Answer: This is the answer
Using the law of cosines, it is found that the distance across the lake is of 978.5 feet.
<h3>What is the law of cosines?</h3>
The law of cosines states that we can find the angle C of a triangle as follows:

in which:
- c is the length of the side opposite to angle C.
- a and b are the lengths of the other sides.
In this problem, the parameters are:
a = 800, b = 900, C = 70º.
Hence the distance across the lake is c, found as follows:

c² = 800² + 900² - 2(800)(900)cos(70º)
c² = 957491

c = 978.5.
The distance across the lake is of 978.5 feet.
More can be learned about the law of cosines at brainly.com/question/2491835
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To solve this problem you must apply the following proccedure:
1. You have that <span>25-foot long board is to be cut into two parts. Then, the first equation is:
a+b=25
2. </span><span>The longer part is one foot more than twice the shorter part:
a=1+2b
3. The system of equation is:
a+b=25
a=1+2b
4. When you solve it, you obtain:
a=25-b
25-b=1+2b
25-1=2b+b
24/3=b
b=8 ft
a=1+2(8)
a=17 ft
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The school is located at (8,7)
The park is located at (10,11)
Using the distance formula: Distance = SQRT(( X2-X1)^2 + (Y2-Y1)^2)
Distance = SQRT((10-8)^2 + (11-7)^2)
Distance = SQRT(2^2 + 4^2)
Distance = SQRT(4+16)
Distance = SQRT(20)
Distance = 2 SQRT 5
Answer:
y = -3x + 4
Step-by-step explanation:
y = mx + c
y = gradient(x intercept) + y intercept
y = -3x + 4