Lesson

# 3.1 RADIAN MEASURE

After completing this section, you should be able to:

• convert between radian and degree angle measurement: $180^{\circ} = \pi$
• find arc length and sector area: $\ell=r \theta, A=\displaystyle \dfrac{1}{2}r^2 \theta$
• find trigonometric ratios using unit circle
• find trigonometric ratios using unit circle in four quadrants
• find angles with particular trigonometric ratios
• find exact ratios in radian
• find the gradient of lines in radian measure: $m = \tan \theta$