Problem 1
Draw a straight line and plot P anywhere on it. Use the compass to trace out a faint circle of radius 8 cm with center P. This circle crosses the previous line at point Q.
Repeat these steps to set up another circle centered at Q and keep the radius the same. The two circles cross at two locations. Let's mark one of those locations point X. From here, we could connect points X, P, Q to form an equilateral triangle. However, we only want the 60 degree angle from it.
With P as the center, draw another circle with radius 7.5 cm. This circle will cross the ray PX at location R.
Refer to the diagram below.
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Problem 2
I'm not sure why your teacher wants you to use a compass and straightedge to construct an 80 degree angle. Such a task is not possible. The proof is lengthy but look up the term "constructible angles" and you'll find that only angles of the form 3n are possible to make with compass/straight edge.
In other words, you can only do multiples of 3. Unfortunately 80 is not a multiple of 3. I used GeoGebra to create the image below, as well as problem 1.
Answer:
slope = 2
Step-by-step explanation:
Calculate the slope m using the slope formula
m = 
with (x₁, y₁ ) = (2, 3) and (x₂, y₂ ) = (4, 7)
m = 
= 
= 2
Answer: t = 6 s
Step-by-step explanation:
When Rose hit the water, the height of the jump is 0, so: h(t) = 0.
Resolving it, we have:
-16t² + 16t + 480 = 0
To simplify the second degree equation, divided it by 16:
-t² + t + 30 = 0
Now, solve the equation using Bhaskara:
Δ = 1² - 4. (-1) . 30
Δ = 1 + 120
Δ = 121
t = 
t₁ = 
= - 5
t₂ = 
= 6
Since time can be negative, it took t = 6s for Rose to hit the water.
Let's rewrite the equation with x and y on the left side of the equal sign.
5x-4y=8 --------(1)
3x-3y=3---------(2)
Divide equation (2) by 3,
x - y= 1
now we have,
5x-4y = 8 --------(1)
x - y = 1 ---------(2)
To eliminate x, multiply equation (2) by 5. This makes both the coefficients of x to be 5. Subtract the second equation from the first equation.
5x - 4y = 8
(2) * 5 5x - 5y = 5
(-) (+) (-)
----------------
0x +y =3
Therefore, y=3
Substitute the value of y, in any one of the two equations. Let's substitute y in the second equation.
x-3=1
x=4
x=4 and y=3
Answer: The ice image, bottom left.
Step-by-step explanation:
The albedo values give information about the proportion of radiation that a given object surfaces, for example, if an object has an albedo value of 0.2, this means that the object reflects 0.2*100% = 20% of the radiation.
You usually can see that darker objects have a smaller albedo value, while clearer objects have a bigger albedo value, meaning that as clearer is the color, usually it reflects a bigger proportion of the radiation.
Here we have that the bigger albedo value is in the ice ( 0.55), so the correct image is the ice image, at the bottom left.
