弧形面積計(jì)算題：已知弧形ABC,其弦長(zhǎng)L=3.24; 矢高h(yuǎn)=0.39.求：弧形ABC的面積.先求弧半徑R .在直角三角形⊿OKC中,R2=（L/2）2 （R – h）2=R2－2hR h2 L2 / 4.得：R = ( h2 L2/4) / 2h =h / 2 L2 / 8h = 0.39 / 2 3.242 /( 8×0.39) = 3.559615385.∠BOC = arcsin(L/2)/R = arcsin1.62/3.559615385 = 27.07171274°.園心角∠AOC = 2∠BOC = 2×27.07171274°= 54.14342548°.再求扇形ABCO面積：扇形ABCO面積 = 3.1416 R2×54.14342548°/360°= 5.986862047.弧形ABC的面積 = 扇形ABCO面積 - 三角形⊿AOC面積 = 5.986862047 – L（R-h）/2 = 5.986862047 – 3.24×(3.559615385–0.39)/2 = 0.852085123.(畫好的圖復(fù)制不過來(lái))
弧形ABC的面積 = 扇形ABCO面積 - 三角形⊿AOC面積
= 5.986862047 – L（R-h）/2
= 5.986862047 – 3.24×(3.559615385–0.39)/2
= 0.852085123.
弧長(zhǎng) = 園周長(zhǎng)×園心角∠AOC / 360°
= 2×3.1416 R×54.14342548°/360°
= 2×3.1416 ×3.559615385×54.14342548°/360°
= 3.363769059.