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
Answer:
2.4 hours
Step-by-step explanation:
David's time = 6 hours
Anthony's time = 4 hours
the combined time is given by the following formula
1/ (david's time) + 1/(anthony's time) = 1/total time
1/6 + 1/4 = 1/Total
4/24 + 6/24 = 1/Total
10/24 = 1/ total (taking reciprocal of both sides)
24/10 = total
total time = 24/10 = 2.4 hours
Answer: -3
The coefficient is the number that is getting multiplied by the variable
100cm is equivalent to 1m so 500cm is equivalent to 5m. What you need to do is divide 500cm (5metres) by 25cm (one quarter of a metre). So the number sentence using 'division' should look like 500cm divided by 25cm which equals 20. Don't forget to use proper symbols for division though. Let me know if this helps:)
