Find the Area of the shaded part Use pi = 3.14. The height is 10dm.

Mchoro unaonyesha mstatili wenye urefu $H = 10 \, \text{dm}$. Ndani ya mstatili huu, kuna maumbo mawili yanayofanana kama matao. Tunachukulia kuwa haya ni nusu-duara. Sehemu zilizotiwa kivuli ni zile sehemu za mstatili ambazo hazijafunikwa na nusu-duara mbili na eneo la mstatili lisilotiwa kivuli katikati yao.

Kipenyo cha kila nusu-duara ni sawa na urefu wa mstatili, $D = H = 10 \, \text{dm}$.
Rediasi ya kila nusu-duara ni $r = \frac{D}{2} = \frac{10 \, \text{dm}}{2} = 5 \, \text{dm}$.

Eneo la nusu-duara moja ni $\frac{1}{2} \pi r^2$.
Eneo la nusu-duara mbili ni $A_{nusu-duara} = 2 \times \frac{1}{2} \pi r^2 = \pi r^2$.
Badilisha $r = 5 \, \text{dm}$:

Upana wa kila nusu-duara ni kipenyo chake, $D = 10 \, \text{dm}$.
Acha upana wa eneo la mstatili lisilotiwa kivuli katikati ya nusu-duara mbili uwe $x$.
Upana wote wa mstatili utakuwa $W = D + x + D = 10 \, \text{dm} + x + 10 \, \text{dm} = (20 + x) \, \text{dm}$.
Urefu wa mstatili ni $H = 10 \, \text{dm}$.
Eneo lote la mstatili ni $A_{mstatili} = W \times H = (20 + x) \, \text{dm} \times 10 \, \text{dm} = (200 + 10x) \, \text{dm}^2$.

Eneo lililotiwa kivuli ni eneo lote la mstatili ukitoa eneo la nusu-duara mbili na eneo la mstatili lisilotiwa kivuli katikati ($A_{kati\_isiyotiwa\_kivuli} = 10x \, \text{dm}^2$).