Answer:
Area of a ring = π (R² – r²)
where R is the outer radius and r is the inner radius of the ring.
Since there are 8 rings, we need to multiply this area by 8 to get the total area:
Total area = 8 × 2.355 m²
Total area = 18.84 m²
Now, to find the cost of painting, we need to multiply the total area by the rate per m², which is $3:
Cost of painting = 18.84 m² × $3/m²
Cost of painting = $56.52
Therefore the cost of painting the rings at $3 per m² is $56.52.