Answer:
Area of the shaded region = 1.72r²
Step-by-step explanation:
Radius of the circle = r
Length of the rectangle = 4r
Width of the rectangle = 2r
Area of the circle = πr²
Area of the rectangle = Length × Width
= 4r × 2r
= 8r²
Area of the shaded region = Area of the rectangle - 2 × Area of the circle
= 8r² - 2 × πr²
= 8r² - 2πr²
= r²(8 - 2π)
= r²(8 - 2 × 3.14)
= r²(8 - 6.28)
= 1.72r² 
C. 10r-3
Because 2r+5=7, the minus 6 and 7 which gives you 1 then minus 4 and 1 witch is 3 then you do 10r-3 and it will get you to 2r+5=7 again. I hope this helped!
Trig ratios can only be used on right triangles with acute measures.
If given an angle and there are adjacent and opposite sides, then use tan(opposite/adjacent)
If given an angle and there is an adjacent side and a hypotenuse, then use cosine(adjacent/hypotenuse)
If given an angle and there is an opposite and adjacent side, then use sin(opposite/hypotenuse)
A common mnemonic device used to memorize the trig rules is SOH-CAH-TOA
In this case we are dealing with the pythagorean theorm involving right angled triangles. This theorm states that a^2 + b^2 = c^2 which means the square of the hypotenuse (side c, opposite the right angle) is equal to the square of the remaining two sides.
In this case we will say that a = 3963 miles which is the radius of the earth. c is equal to the radius of the earth plus the additional altitude of the space station which is 250 miles; therefore, c = 4213 miles. We must now solve for the value b which is equal to how far an astronaut can see to the horizon.
(3963)^2 + b^2 = (4213)^2
b^2 = 2,044,000
b = 1430 miles.
The astronaut can see 1430 miles to the horizon.
The perimeter is 36 and the area is 81 units
hope this helps:)
