Tam giác ABC đều có đường trung tuyến AM nội tiếp đường tròn (O; 4 cm). Độ dài AM bằng

A. \[\frac{{\sqrt 3 }}{7}\] cm.

B. \[2\sqrt 3 \] cm.

C. \[7\sqrt 3 \] cm.

D. \[\frac{{7\sqrt 3 }}{3}\] cm.

A. \[7\pi \sqrt 3 \] cm.

B. \[\frac{{7\sqrt 3 }}{3}\] cm.

C. \[\frac{{7\pi \sqrt 3 }}{3}\]cm.

D. \[\frac{{7\pi \sqrt 3 }}{9}\] cm.

A. \[2\sqrt 3 \] cm.

B. \[\sqrt 3 \] cm.

C. \[\frac{{2\sqrt 3 }}{3}\] cm.

D. \[\frac{{\sqrt 3 }}{2}\] cm.

A. \[\frac{{3\sqrt 3 }}{3}\] cm.

B. \[3\sqrt 3 \] cm.

C. \[\frac{{3\sqrt 3 }}{2}\] cm.

D. \[\frac{{9\sqrt 3 }}{2}\] cm.

A. \[\frac{{25\pi }}{3}\] m².

B. \[\frac{{25\sqrt 3 }}{3}\] m².

C. \[\frac{{25\pi \sqrt 3 }}{3}\] m².

D. \[\frac{{25\pi \sqrt 3 }}{9}\] m².

A. \[\frac{{5\sqrt 3 }}{2}\] cm.

B. \[\frac{{5\sqrt 3 }}{6}\] cm.

C. \[5\sqrt 3 \] cm.

D. \[\frac{{5\sqrt 3 }}{3}\] cm.

A. \[2\sqrt 3 \] cm.

B. \[\frac{{12\sqrt 3 }}{6}\] cm.

C. \[4\sqrt 3 \] cm.

D. \[\frac{{4\sqrt 3 }}{3}\] cm.