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Category: Geometry

related-to-Q-19333-the-side-lengthes-of-a-triangle-are-integer-if-the-perimeter-of-the-triangle-is-100-how-many-different-triangles-exist-what-is-the-maximum-area-of-them-

Question Number 19388 by mrW1 last updated on 10/Aug/17 $$\mathrm{related}\:\mathrm{to}\:\mathrm{Q}.\mathrm{19333} \\ $$$$\mathrm{the}\:\mathrm{side}\:\mathrm{lengthes}\:\mathrm{of}\:\mathrm{a}\:\mathrm{triangle}\:\mathrm{are}\: \\ $$$$\mathrm{integer}.\:\mathrm{if}\:\mathrm{the}\:\mathrm{perimeter}\:\mathrm{of}\:\mathrm{the}\:\mathrm{triangle} \\ $$$$\mathrm{is}\:\mathrm{100},\:\mathrm{how}\:\mathrm{many}\:\mathrm{different}\:\mathrm{triangles} \\ $$$$\mathrm{exist}?\:\mathrm{what}\:\mathrm{is}\:\mathrm{the}\:\mathrm{maximum}\:\mathrm{area}\:\mathrm{of} \\ $$$$\mathrm{them}? \\ $$ Commented by mrW1…

Question-150451

Question Number 150451 by ajfour last updated on 12/Aug/21 Commented by Ar Brandon last updated on 12/Aug/21 $$\mathrm{I}\:\mathrm{admire}\:\mathrm{your}\:\mathrm{posts}\:\mathrm{sir}.\:\mathrm{Sadly}\:\mathrm{I}\:\mathrm{have}\:\mathrm{very}\:\mathrm{little}\:\mathrm{knowledge} \\ $$$$\mathrm{on}\:\mathrm{geometry}.\:\mathrm{You}'\mathrm{re}\:\mathrm{so}\:\mathrm{advanced}.\:\mathrm{Hahaha}\:!\:\mathrm{I}\:\mathrm{hope}\:\mathrm{I}\:\mathrm{will}\:\mathrm{get} \\ $$$$\mathrm{there}\:\mathrm{someday}. \\ $$ Commented…

Question-84899

Question Number 84899 by Power last updated on 17/Mar/20 Commented by Tony Lin last updated on 17/Mar/20 $${A}\left({ADE}\right)=\mathrm{9} \\ $$$$\Rightarrow{h}=\mathrm{6} \\ $$$${A}\left({EFC}\right) \\ $$$$=\frac{\mathrm{1}}{\mathrm{2}}×{EC}×\left({h}×\frac{\mathrm{6}}{\mathrm{7}}\right) \\…

Question-150418

Question Number 150418 by ajfour last updated on 12/Aug/21 Commented by ajfour last updated on 12/Aug/21 $${For}\:{tetrahedron}\:{edge}\:{a}, \\ $$$${and}\:{sphere}\:{radius}\:{r},\:{find}\: \\ $$$${fractional}\:{volume}\:{of}\:{sphere}\: \\ $$$${within}\:{the}\:{tetrahedron}. \\ $$$${f}=\begin{cases}{{g}_{\mathrm{1}}…

Question-150376

Question Number 150376 by cherokeesay last updated on 11/Aug/21 Commented by liberty last updated on 12/Aug/21 $$\left(\mathrm{2}\sqrt{\mathrm{3}}+\mathrm{r}\right)^{\mathrm{2}} =\left(\mathrm{4}\sqrt{\mathrm{3}}−\mathrm{r}\right)^{\mathrm{2}} +\left(\mathrm{2}\sqrt{\mathrm{3}}−\mathrm{r}\right)^{\mathrm{2}} \\ $$$$\mathrm{let}\:\mathrm{2}\sqrt{\mathrm{3}}\:=\:{a} \\ $$$$\Rightarrow\left({a}+{r}\right)^{\mathrm{2}} −\left({a}−{r}\right)^{\mathrm{2}} =\left(\mathrm{2}{a}−{r}\right)^{\mathrm{2}}…

Let-AC-be-a-line-segment-in-the-plane-and-B-a-point-between-A-and-C-Construct-isosceles-triangles-PAB-and-QBC-on-one-side-of-the-segment-AC-such-that-APB-BQC-120-and-an-isosceles-triangle-RAC-

Question Number 19293 by Tinkutara last updated on 08/Aug/17 $$\mathrm{Let}\:{AC}\:\mathrm{be}\:\mathrm{a}\:\mathrm{line}\:\mathrm{segment}\:\mathrm{in}\:\mathrm{the}\:\mathrm{plane} \\ $$$$\mathrm{and}\:{B}\:\mathrm{a}\:\mathrm{point}\:\mathrm{between}\:{A}\:\mathrm{and}\:{C}. \\ $$$$\mathrm{Construct}\:\mathrm{isosceles}\:\mathrm{triangles}\:{PAB}\:\mathrm{and} \\ $$$${QBC}\:\mathrm{on}\:\mathrm{one}\:\mathrm{side}\:\mathrm{of}\:\mathrm{the}\:\mathrm{segment}\:{AC} \\ $$$$\mathrm{such}\:\mathrm{that}\:\angle{APB}\:=\:\angle{BQC}\:=\:\mathrm{120}°\:\mathrm{and} \\ $$$$\mathrm{an}\:\mathrm{isosceles}\:\mathrm{triangle}\:{RAC}\:\mathrm{on}\:\mathrm{the}\:\mathrm{other} \\ $$$$\mathrm{side}\:\mathrm{of}\:{AC}\:\mathrm{such}\:\mathrm{that}\:\angle{ARC}\:=\:\mathrm{120}°. \\ $$$$\mathrm{Show}\:\mathrm{that}\:{PQR}\:\mathrm{is}\:\mathrm{an}\:\mathrm{equilateral} \\…

Let-ABCD-be-a-parallelogram-Two-points-E-and-F-are-chosen-on-the-sides-BC-and-CD-respectively-such-that-EB-EC-m-and-FC-FD-n-Lines-AE-and-BF-intersect-at-G-Prove-that-the-ratio-

Question Number 19238 by Tinkutara last updated on 07/Aug/17 $$\mathrm{Let}\:{ABCD}\:\mathrm{be}\:\mathrm{a}\:\mathrm{parallelogram}.\:\mathrm{Two} \\ $$$$\mathrm{points}\:{E}\:\mathrm{and}\:{F}\:\mathrm{are}\:\mathrm{chosen}\:\mathrm{on}\:\mathrm{the}\:\mathrm{sides} \\ $$$${BC}\:\mathrm{and}\:{CD},\:\mathrm{respectively},\:\mathrm{such}\:\mathrm{that} \\ $$$$\frac{{EB}}{{EC}}\:=\:{m},\:\mathrm{and}\:\frac{{FC}}{{FD}}\:=\:{n}.\:\mathrm{Lines}\:{AE}\:\mathrm{and}\:{BF} \\ $$$$\mathrm{intersect}\:\mathrm{at}\:{G}.\:\mathrm{Prove}\:\mathrm{that}\:\mathrm{the}\:\mathrm{ratio} \\ $$$$\frac{{AG}}{{GE}}\:=\:\frac{\left({m}\:+\:\mathrm{1}\right)\left({n}\:+\:\mathrm{1}\right)}{{mn}}. \\ $$ Commented by ajfour…