Answer:
circumference: 5.65 m
area: 2.54 m
Step-by-step explanation:
here are some relationships between measurements of a circle:
C = π d
(Circumference = pi · diameter)
A = π r²
(Area = pi · radius²)
[π / pi is the ratio of a circle's circumference to its diameter. this ratio is actually a constant across all circles, which is where we derive our circumference and area formula from. π ≈ 3.14159]
so, let's work on finding the circumference first.
C = π d
we know the diameter = 1.8, and we know that π ≈ 3.14159
so, if we multiply these two numbers together, we will get the circumference
[this equation makes sense if you read my explanation of pi]
1.8 × 3.14159 = 5.654862
We can round this number to 5.65
So, the circumference of our circle = 5.65 m
now, let's find the area
A = π r²
we know that π ≈ 3.14159, but we still haven't found "r"
r, or radius, is the measurement from the center of a circle to any point of the circle. Because the diameter is the measurement from one side of a circle to the opposite side, diameter = twice the radius
this means we can take our diameter, 1.8, and divide it by 2 to find our radius.
1.8 / 2 = 0.9
now, we can solve for area.
π ≈ 3.14159 , r = 0.9
A = π r²
A = π (0.9)²
A = (3.14159) (0.81)
A = 2.5446879
we can round this area to 2.54
so, the area of our circle = 2.54 m
