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15 votes
15 votes
the surface area of a pyramid is 85 square meters the side length of the base is 5 meters what is the slant height

User Ryan Wilson
by
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2 Answers

7 votes
7 votes

Answer:

6 meters

Explanation:


A=a^2+2a\sqrt{(a^2)/(4)+h^2}is the formula that you use

h=vertical altitude and

a=side length of the base


85=5^2+(2*5)\sqrt{(25)/(4)+h^2}


85-25=10\sqrt{(25)/(4)+h^2}


(60)/(10)=\sqrt{(25)/(4)+h^2}


6=\sqrt{(25)/(4)+h^2}


36=(25)/(4)+h^2


36-(25)/(4)=h^2


36-6.25=h^2


29.75=h^2

Vertical altitude (h) and
(1)/(2)a and the slant height form a right triangle with the slant height being the hypotenuse


h^2+(2.5)^2=s^2where s=slant height


29.75+6.25=s^2


36=s^2

s=6 meters

User Ntamjo Achille
by
3.0k points
17 votes
17 votes

Answer:

slant height = 6 meters

Explanation:

surface area of pyramid: 2bs + b²

2*5*s + 5² = 85

10s = 85 - 25

10s = 60

s = 6

The slant height is 6 meters.

User Grigori Melnik
by
2.9k points