This is the rule of sums of trig identities. It says that sin(a + b) = sina*cosb+sinb*cosa. Set up your right triangles. In a 30-60-90 triangle, the side across from the 60 angle is the square root of 3, the side across from the 30 is 1, and the hypotenuse is 2. In a 45-45-90 the sides across from the 45 degree angles are 1 and the hypotenuse is square root of 2. With that being said, the sin of 60 is 
and the cos of 60 is 1/2. Both the sin and cos of 45 is 
. So your formula is filled in like this: 
. When you do the multiplication on those sets of parenthesis, you get 
. When you add those your solution is 
. Depending upon your instructor you may have to rationalize that denominator to get that radical out from under there, but if not, that's pretty much it!
PLEASE HELP ME ASAP!
1 answer:
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Answer:
31/40
Step-by-step explanation:
The question is incomplete. Here is the complete question with appropriate diagram.
The circle below has an area of 314 square centimeters, and the square inside the circle has a side length of 2 centimeters.
What is the probability that a point chosen at random is in the blue region?
Given the area of the circle to be 314cm², we need to get the diameter of the circle first since the diameter of the circle is equivalent to length of the side of the square inscribed in it.
Using the formula Area of a circle = πr²
314 = 3.14r²
r² = 314/3.14
r² = 100
r = 10 cm
Diameter of the circle = 2*10 = 20 cm
Area of a square = Length * length
Area of the outer square = 20*20 = 400cm²
Area of the inner square with side length 2cm = 2*2 =4cm²
Area of the shaded region = Area of the square - Area of the inner square
= 314-4 = 310cm²
The probability that a point chosen at random is in the blue region = Area of the shaded region/total area of the outer square
= 310/400
= 31/40
