Tolong dijawab ya.. Jawabnya jangan ngasal ya..

Menggunakan teorema phytagoras
XY = a
OX = 1/2 a

[tex]YO= \sqrt{a^2-( \frac{1}{2}a)^2 } \\ \\ YO= \sqrt{a^2-\frac{1}{4}a^2 }\\ \\ YO= \sqrt{\frac{4}{4}a^2-\frac{1}{4}a^2 }\\ \\ YO= \sqrt{\frac{3}{4}a^2 }\\ \\ YO= \sqrt{\frac{a^2}{4}\times3 } \\ \\ YO= \sqrt{\frac{a^2}{2^2}} \times \sqrt{3} \\ \\ YO= \frac{1}{2}a \times \sqrt{3} =\frac{1}{2}a \sqrt{3}............\text{Jawaban (D)} [/tex]

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