Answer:
2. x
² + y
²
= 4
3. x² + y² = 23
Step-by-step explanation:
The equation of a circle with center
(
a
,
b
) and radius r is:
(
x
−
a
)²
+ (
y
−
b
)
² = r
²
Explanation:
Here,
a
=
0
, b
=
0
, r
=
2
The equation is:
(
x
-0
)
² + (
y
-0
)
² = (
2 )
²
that is: x
² + y
² = 4
Thus:
x
² + y
²
= 4
3. Each point on a circle has the same distance from the center. This distance is the radius r of the circle.
Here,
(
-3
,
4
) is a point on the circle, meaning that the radius of the circle is the distance between (
0
,
0
)
, the center, and (
-3
,
4
)
.
thus a circle centered on the origin will have an equation of:
x² + y² =r²
And, (
-3
,
4
) lies on the circle, we have:
(-3)² + (4)² = r²
9 + 14 = 23
substituting;
x² + y² = 23
