Acircle has its center at (0,0) and passes through the point (0,9). what is the standard equation of the circle?

x^2+y^2=9^2

Step-by-step explanation:

The standard equation of a circle is:

Where the center of a circle is (h,k) and r is the radius of the circle.  In this case because a circle is equidistant from the center and we have a point where it passes through 9 that means that the radius is 9.  However, since the standard equation states that we must write r in the form of this means that .  Therefore by plugging in the values we have:

option a, c,d are correct.

step-by-step explanation:

from the given figure, it is given that z is equidistant from the sides of the triangle rst, then from triangle tzb and triangle szb, we have

tz=sz(given)

bz=zb(common)

therefore, by rhs rule,δtzb ≅δszb

by cpctc, sz≅tz

also, from δctz and δasz,

tz=sz(given)

∠tcz=∠saz(90°)

by rhs rule, δctz ≅ δasz, therefore by cpctc, ∠ctz≅∠asz

also,from δasz and δzsb,

zs=sz(common)

∠zbs=∠saz=90°

by rhs rule, δasz ≅δzsb, therefore, by cpctc, ∠asz≅∠zsb

hence, option a, c,d are correct.