Suppose that circles r and s have a central angle measuring 80°. additionally, the measure of the sector for circle r is 32 9 π m2 and for circle s is 18π m2. if the radius of circle r is 4 m, what is the radius of circle s? a) 6 m b) 9 m c) 12 m d) 15 m

The correct answer is B) 9 m.

The measure of the sector of circle R is 32π/9 m.  The measure of the central angle is 80°.  This means that the sector is 80/360 = 2/9 of the circle.  The area of a circle is given by A=πr², so the area of the sector is A=2/9πr².  To verify this, 2/9π(4²) = 2/9π(16) = 32π/9.

Using this same formula for circle S, we will work backward to find the radius:

18π = 2/9πr²

Multiply both sides by 9:
18*9π = 2πr²
162π = 2πr²

Divide both sides by 2π:
162π/2π = 2πr²/2π
81 = r²

Take the square root of both sides:
√81 = √r² 
9 = r

the law of definite proportions states samples of a compound will always contain the same proportion of elements by mass. in other words, a given compound will always contain the same elements in the same proportions by mass.the law of multiple proportions states when two elements combine with each other to form more than one compound, then the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.