Length of arc, L = 21.4 - 2 x 4.2cm
= 21.4 - 8.4
= 13cm
But L = θ360∘\frac{\theta}{360^{\circ}}360∘θ x 2πr\pi rπr
i.e 13 = θ360∘\frac{\theta}{360^{\circ}}360∘θ x 2 x 227\frac{22}{7}722 x 4.2
= 13 x 360∘^{\circ}∘ x 7
= θ\thetaθ x 2 x 22 x 4.2
θ\thetaθ = 13×360∘×744×4.2\frac{13 \times 360^{\circ} \times 7}{44 \times 4.2}44×4.213×360∘×7
= ≈\approx≈ 177.27∘^{\circ}∘
≈\approx≈ 177∘^{\circ}∘ (to the nearest degree)
