θ360\; \frac{\theta}{360}360θ * 2 * π * r → 150 × 2 × 22 × 4.2360 x 7\; \frac{150\; \times\; 2\; \times\; 22\; \times\; 4.2}{360\; x\; 7}360x7150×2×22×4.2
= 11cm
