Matematika

Pertanyaan

10° + 20° + ... + 200° = ...
a.
[tex]11 \frac{2}{3} \pi[/tex]
b.
[tex]12 \frac{1}{3} \pi[/tex]
c.
[tex]12 \frac{2}{3} \pi[/tex]
d.
[tex]13 \frac{1}{3} \pi[/tex]
e.
[tex]13 \frac{2}{3} \pi[/tex]

1 Jawaban

  • Un = a + (n - 1)b
    200 = 10 + (n - 1) 10
    200 = 10 + 10n - 10
    200 = 10n
    n = 200 / 10
    n = 20

    [tex]s20 = \frac{20}{2} (2(10) + (20 - 1)10) \\ s20 = 10(20 + 190) \\ s20 = 10(210) \\ s20 = 2100 \\s20 = \frac{35}{3} \times 180 \\ s20 = 11 \ \frac{2}{3} \times 180 \\ s20 = 11 \ \frac{2}{3} \pi[/tex]
    jawabannya a

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