bantuin dong pke cara mau di kumpul hari ini

a)
[tex] = \frac{1}{2} \pi \: d {}^{2} \\ = \frac{1}{2} 3.14 \times {50}^{2} \\ = \frac{1}{2} \times 7850 \\ = 3925[/tex]
b)
[tex] \frac{1}{4} \times \pi \: r {}^{2} \\ = \frac{1}{4} \times \frac{22}{7} \times {14}^{2} \\ = \frac{1}{4} \times 44 \times 14 \\ = \frac{1}{4} \times 616 \\ = 154[/tex]
d)Luas Persegi panjang=100×14=140
Luas 1/2 lingkaran=
[tex] \frac{1}{2} \times 3.14 \times {100}^{2} \\ = \frac{1}{2} \times 31400 \\ = 15700[/tex]