The diagram shows a circle ${C_1}$ touching a circle ${C_2}$ at a point $X$. Circle ${C_1}$ has centre $A$ and radius $6{\text{ }}cm$, and circle ${C_2}$ has centre $B$ and radius $10{\text{ }}cm$. Points $D$ and $E$ lie on ${C_1}$ and ${C_2}$ respectively and $DE$ is parallel to $AB$. Angle $DAX = \frac{1}{3}\pi $ radians and angle $EBX = \theta $ radians.
a) By considering the perpendicular distances of $D$ and $E$ from $AB$, show that the exact value of $\theta $ is ${\sin ^{ - 1}}\left( {\frac{{3\surd 3}}{{10}}} \right)$.
b) Find the perimeter of the shaded region, correct to 4 significant figures.

پاسخ تشریحی :
تحلیل ویدئویی تست
تحلیل ویدئویی برای این تست ثبت نشده است!