# Thread: Math help - Length

1. ## Math help - Length

A farmer has 2 grasshoppers of the same species.The coresponding parts of the grasshopper's bodies are proportional.The larger grasshopper has an 8cm body and a 1.5cm forelimb.The smaller grasshopper has a 1.2cm forelimb.How long is the body of the smaller grasshopper.
(a)10.0cm
(b)7.7cm
(c)6.4cm
(d)6.6cm

2. Originally Posted by devi
A farmer has 2 grasshoppers of the same species.The coresponding parts of the grasshopper's bodies are proportional.The larger grasshopper has an 8cm body and a 1.5cm forelimb.How long is the body of the smaller grasshopper.
(a)10.0cm
(b)7.7cm
(c)6.4cm
(d)6.6cm
We are missing one piece of information here: the length of the forelimb of the smaller grasshopper.

I don't see how we can answer this question without that bit of information.

--Chris

3. Originally Posted by Chris L T521
We are missing one piece of information here: the length of the forelimb of the smaller grasshopper.

I don't see how we can answer this question without that bit of information.

--Chris
Sorry.It is a mistake on my part.

4. Originally Posted by devi
A farmer has 2 grasshoppers of the same species.The coresponding parts of the grasshopper's bodies are proportional.The larger grasshopper has an 8cm body and a 1.5cm forelimb.The smaller grasshopper has a 1.2cm forelimb.How long is the body of the smaller grasshopper.
(a)10.0cm
(b)7.7cm
(c)6.4cm
(d)6.6cm
Set up a proportion:

$\frac{\text{body length of small grasshopper}}{\text{body length of large grasshopper}}=\frac{\text{forearm length of small grasshopper}}{\text{forearm length of large grasshopper}}$

This implies that $\frac{L}{8~cm}=\frac{1.2~cm}{1.5~cm}$

Thus, $L=\frac{1.2}{1.5}(8~cm)=\dots$

Can you finish this?

--Chris