How did the musician keep his sousaphone clean?

Answer:#1) I; #2) W; #3) S; #4) E; #5) A; #6) O; #7) U; #8) H; #9) B; #10) P; #11) TStep-by-step explanation:#1)  For ray DB, we want a symbol whose first letter is D, second letter is B and has a picture of a ray (arrow at one end) above it.  This is I.#2) For line DB, we want the letters D and B in that order with a line (arrows at both ends) over it  This is W.#3) For segment DB, we want the letters D and B in that order with a line segment (no arrows) over it.  This is S.#4) For the ray opposite DB, we would want the ray DL.  This means we want the letters D and L in that order with a ray (arrow at one end) over it.  This is E.#5) Ray DB and segment RA intersect at point A.  This is choice A.#6) Since A is between D and B, this would give us DAB, or D-A-B.  This is O.#7) The length of segment DB is shown as just the two letters of the segment with nothing over it.  This is U.#8) Segment DM and MA together make segment DA, or AD.  The length of this segment would be written as either DA or AD; this is H.#9) The endpoint of ray BA is B.  This is choice B.#10) The union of LD and DM is segment LM.  This is choice P.#11) The intersection of ray DS and ray SD is segment DS.  This is choice T.