If a circle has an area of 84π units then what is the measure of its radius in exact units?
a. 2√21 units
b. √ 54 units
C 10.4 units
d. 108 units

Answer quickly please

a. 2√21 units

Hi there !

Area formula

A = π·r²

84π = πr²

r² = 84π/π

r² = 84

r² = 2²×3×7

r = √2²×3×7

r = 2√3×7

r = 2√21

Good luck !

they can both be solutions depends on the equation

step-by-step explanation:

what is the equation? ?

guess at question:

a vertical line intersects the graph of g(x,y) = 0 at two points. what conclusion follows about the function f(x) implicitly defined by g(x,f(x)) = 0?

the domain of f(x) cannot include the x coordinate of any such vertical line.

informally, f(x) is not a function, and

g(x,y)=0 cannot be solved for y uniquely.

the relation r = {(x,y) such that g(x,y) = 0} is a function if

for all (a,b) ∊ r and (c,d) ∊ r, a=c implies b=d.

step-by-step explanation: