Answer:
1,256 dm^2 and 400π dm^2
Step-by-step explanation:
The circumference is equal to 2pi times the radius. So 40pi=2pi times the radius so the radius is 20. The area of a circle is pi times the radius squared or 400pi and if using 3.14 for pi this would be 1,256 dm^2
Answer:
28
Step-by-step explanation:
9-6/3=9-2=7
4*7=28
Answer:
centre = (2, 4)
Step-by-step explanation:
The equation of a circle in standard form is
(x - h)² + (y - k)² = r²
where (h, k) are the coordinates of the centre and r is the radius
Given
x² + y² - 4x - 8y - 5 = 0
Rearrange the x/y terms together and add 5 to both sides
x² - 4x + y² - 8y = 5
Use the method of completing the square on both the x/y terms
add ( half the coefficient of the x/y terms )² to both sides
x² + 2(- 2)x + 4 + y² + 2(- 4)y + 16 = 5 + 4 + 16
(x - 2)² + (y - 4)² = 25 ← in standard form
with centre (2, 4) and r =
= 5