(65)247. COROL. Ope quadrati distan-tiam, ad cujus unum punctum accessusdatur, reperies, ut N. 244.248. PROBL. Metiri distantiam BL F.planè inaccessam.31.SOLUTIO. I. Per mensulam. Ele-ctis duabus stationibus R & S, ex quibusextrema puncta B & L conspici queant,I. Mensulâ in R positâ, delinea angulosBRL & LRS, ductis rectis Ad, AV,AC, ut dictum suprâ (240) II. Mensu-lam transfer ex R in S: intervallum ve-ròRS in rectam AC transfer ex A in Osecundùm scalae proportionem, mensu-láque ritè collocatâ (240) delinea quo-que angulum LSB, ductis rectis OV &Od: hae secabunt rectas in prima statio-ne ductas. Quare III. sectionum pun-cta d & V connecte rectâ dV, eámquecircino interceptam scalae applica: quotea partes decimas &c. continet, tot per-ticas &c. complectitur BL.DEMONST. Quoniam in triangulisBRS & dAO, item LRS, & VAO, exconstr. duo sunt anguli mutuò aequa-les; erit Rs: AO=BS: dO, & Rs:AO=LS:VO(216) adeóque BS:dO-LS: VO(51) quia ergo angulus BSL-dOVex constr., erit BS:dO=BL:dV(218) Ex demonstratis autem BS: dO=RS: AO, ergo BL:dV=RS:AO(51) quia ergo ex constr. Rs tot conti-net