Question

3. The pentagons below are similar. The area of the smaller pentagon is 30 m2. What is the area of the larger pentagon in m2?

187.5 m2
48 m2
75 2
133 m2

Answer 1

umm.. posting a diagram would be an idea :)

Answer 2

Ha I know i had to snip it

Answer 3

since they are similar, their corresponding sides are in equal ratio...
then
\[A\propto a^2\\
{A_{\rm big}\over A_{\rm small}}={a_{\rm big}^2\over a_{\rm small}^2}\\
{A_{\rm big}\over30}={10^2\over4^2}\]

Answer 4

So am I supposed to cross multiply?

Answer 5

yep.
get the \(A_{\rm big}\)

Answer 6

so 30*10^2 = 3000

Answer 7

but did you follow how I set up the ratios?

Answer 8

yes

Answer 9

yes. continue...

Answer 10

OK so then what do i do with the 16

Answer 11

Hello?