Estimate the order of magnitude of the length, in meters, of each of the following: (a) a mouse, (b) a pool cue, (c) a basketball court, (d) an elephant, (e) a city block.

A) a mouse, to an order of magnitude = 0.1 m ( a tenth of a meter ) That would be a big mouse but the alternatives are 1 meter or one hundredth of a meter... so go with 1/10th 

b) Easy = 1 meter 

c) two choices 10m or 100 m . Go with 100 m 

d) Stretch it out , trunk tip to tail tip - call it 10 m 

e) Your choice 100 m or 1000 m These are estimates. So long as you are within one order of magnitude you can't really be given wrong. So I'd say 100m

Distance^2= yellow line ^2 (see picture) = 30^2 + 49^2so distance = squareroot of (300^2 +49^2)i dont know if this is how to solve it, but i cnt think of another way