JAMB - Mathematics (1997 - No. 26)
A cone with a sector angle of 45° is cut out of a circle of radius r cm. Find the base radius of the cone.
\(\frac{r}{16}\) cm
\(\frac{r}{6}\) cm
\(\frac{r}{8}\) cm
\(\frac{r}{2}\) cm
คำอธิบาย
The formula for the base radius of a cone formed from the sector of a circle = \(\frac{r \theta}{360°}\)
= \(\frac{r \times 45°}{360°}\)
= \(\frac{r}{8} cm\)