Given,
The ratio in surface area of two similar pyramid is 25: 36.
The slant height of the larger pyramid is 18 cm.
Required
The slant height of the smaller pyramid.
Consider, the slant height of smaller pyramid is x.
The surface area of the pyramid is calculated as,
[tex]\begin{gathered} \sqrt{\frac{25}{36}}=\frac{x}{18} \\ \frac{5}{6}=\frac{x}{18} \\ x=\frac{5\times18}{6} \\ x=15\text{ cm} \end{gathered}[/tex]
Hence, the slant height of the smaller pyramid is 15 cm.
