Panjang Busur Lingkaran

Jawaban: C

\(\widehat {AB}= \dfrac{\theta}{360^{\circ}} \times 2\pi r\)

\(\widehat {AB}= \dfrac{60^{\circ}}{360^{\circ}} \times 2\cdot \dfrac{22}{\cancel{7}} \cdot \cancel{7}\)

\(\widehat {AB}= \dfrac{1}{6} \times 44\)

\(\widehat {AB}= \dfrac{44}{6} = \dfrac{22}{3} \text{ cm}\)

Jawaban: D

\(\dfrac{\widehat {AB}}{\widehat {CD}} = \dfrac{\dfrac{25^{\circ}}{360^{\circ}} \times 2\pi r}{\dfrac{175^{\circ}}{360^{\circ}} \times 2\pi r}\)

\(\dfrac{\widehat {AB}}{\widehat {CD}} = \dfrac{\dfrac{25^{\circ}}{\cancel{360^{\circ}}} \times \cancel{2\pi r}}{\dfrac{175^{\circ}}{\cancel{360^{\circ}}} \times \cancel{2\pi r}}\)

\(\dfrac{8}{\widehat {CD}} = \dfrac{25^{\circ}}{175^{\circ}}\)

\(\dfrac{8}{\widehat {CD}} = \dfrac{1}{7}\)

\(\widehat {CD} = 7 \times 8 = 56 \text{ cm}\)

Jawaban: D

\(\text{Panjang busur} = \dfrac{\theta}{360^{\circ}} \times 2\pi r\)

\(44 = \dfrac{\theta}{360^{\circ}} \times 2\cdot \dfrac{22}{\cancel{7}} \cdot \cancelto{3}{21}\)

\(44 = \dfrac{\theta}{360^{\circ}} \times 132\)

\(\dfrac{44}{132} = \dfrac{\theta}{360^{\circ}}\)

\(\dfrac{1}{3} = \dfrac{\theta}{360^{\circ}}\)

\(\theta = \dfrac{1}{3} \times 360^{\circ}\)

\(\theta = 120^{\circ}\)