Posted by Anonymous on .
a male black widow spider is half the size of a female black widow spider. together they are 21 millimeter in length. how big is a female black widow

3rd grade math 
Writeacher,
Divide 21 by 3.
The female is 2 of those thirds.
The male is 1 of those thirds. 
3rd grade math 
izah,
the solution is.......17,