No 11371, Friday 17 Apr 2015, Gridman

Gridman's reminiscing about his Geometry class in school.

ACROSS
1   Two musical instruments combined into a third one (8) HORNPIPE {HORN}{PIPE} Semi&lit

5   X working exactly (4,2) SPOT ON {SPOT} {ON}
9   One who puts on a cap (7) LIMITER [CD]
10 OT, a round figure (7) CIRCLET {CIRCLE}{T}
11 A sort of equipment for sight-seer (9) BINOCULAR [CD]
12 A number caught in this Latin confusion (5) HAVOC {H{A}{V}OC}
13 Serious! Without a flap, home is made! (4) NEST earNEST
14 Disgusting! Salesman at far end of Thimpu lives badly (9) REPULSIVE {REP}{t...pU}{LIVES*}
17 Gentlemen get somewhat dear in exchanges (5-4) TRADE-OFFS {T{DEAR*}-OFFS}
19 Throw a fit! Fellow overlooked a mistake (4) GOOF {GO OFf}
23 Proportion provided by real tailor, oddly (5) RATIO ReAl TaIlOr
24 Spends time in the country, catching unwary liar in tricks (9) RURALISES {RU{LIAR*}SES}
25 Get hold of first-class piece of mortar and prepare for firing (4,3) TAKE AIM {TAKE} {A1}{Mo...r}
26 Bliss in perfecting nivaran (7) NIRVANA*
27 Box detective come back to hold query (6) CASKET {C{ASK}ET<=}
28 Maybe, get round to having an amount of computer space (8) MEGABYTE*

DOWN
1   Rashly determined — on way to damnation (8) HELLBENT {HELL}{BENT}
2   Fills a memory gap concerning watches (7) REMINDS {RE}{MINDS}
3   Places church in a revolting situation (6) PUTSCH {PUTS}{CH}
4   Piece of writing three learners, taking a quarter, presented to old Indian village figure (13) PARALLELOGRAM {PARA}{LL{E}L}{O}{GRAM}
6   Thing bought is tea in a bag (8) PURCHASE {PUR{CHA}SE}
7   Capital tale spun out by victors surrounding one (3,4) TEL AVIV {TEL A}*{V{1}V}
8   See, it's thawed (6) NOTICE {NOT}{ICE}
10 One might calculate it roundly (13) CIRCUMFERENCE [CD]
15 Recommend a barrister (8) ADVOCATE [DD]
16 Where behind-the-scene action takes place (8) OFFSTAGE [CD]
18 New shoots? (7) RETAKES [CD]
20 Somewhat rosy about Australia returning burial urn (7) OSSUARY {OS{SUA<=}RY*}

21 Judge top commander holding incomplete ritual (6) CRITIC {C{RITe}IC}
22 Song of praise — one in largo rendered (6) GLORIA {GLOR{1}A*}

GRID