Question

David made this model of a pyramid. Which option best describes the length of the unknown side of David’s pyramid? (picture below)

Answer 1

POSSIBLE ANSWERS:
A less than 4 cm
B greater than 24 cm
C between 4 cm and 20 cm
D between 20 cm and 24 cm

I think it is C but im not sure.. can someone help me figure out how to do this..?

Answer 2

let x be the length
for it to be a triangle , sum of 2 sides must be greater than the third side
therefore
12+8 > x x<20
8+x > 12 ==> x>4
12+x>8 x> -4
combine the above answer, you'll get 4<x<20 that is C

Answer 3

the system of inequality is the 'and' case not 'or'

Answer 4

it would have to be 12cm to be a proper pyramid... so i would say C is the answer. :]

Answer 5

So i was right ? because doesnt the third side needa be longer than both of the legs ?

Answer 6

yeah.. hmm.. yeah it would be true.. but as long as 2 sides are bigger than the other number, then yur good. :P

Answer 7

ohk thanks guys ! :D