Question

9.

The surface area of the right square pyramid shown is 129.5 cm. The base is 4.5 cm. Determine the slant height, s, of this
pyramid, rounded to the nearest tenth

Answer 1

Slant height (s)= 12.1 cm

Explanation:

Given: Base= 4.5 cm.

Surface area of right square pyramid= 129.5 cm.

First, calculating slant height (s) of right square pyramid.

Surface area of square pyramid=
`(a^(2) +2* a* s)`

a= side of square base.

s= slant height

∴
`129.5= (4.5^(2) + 2* 4.5* s)`

⇒
`129.5= (20.25+2* 4.5* s)`

⇒
`129.5= (20.25+9* s)`

Now, opening the parenthesis and subtracting both side by 20.25.

⇒
`109.25=9* s`

cross multiplying both side

∴ Slant height (s)= 12.1