hitunglah panjang diameter bila luas lingkaran 154cm(kuadrat)

jawab

lingkaran

Luas = 154 cm²

pi.r² = 154
r² = 154 : 22/7 = 49
r = 7 cm

[tex]154 \: {cm}^{2} = \frac{22}{7} \times r \times r \: = \\ {r}^{2} = 154 \div \frac{22}{7} = \\ 154 \times \frac{7}{22} = 49 \\ {r}^{2} = 49 . \: \: r \: = 7 \\ d \: = 7 \times 2 = 14 \: cm[/tex]