$$ \\\\ $$ Given, $$CF+FD=12 \\\\ $$ If two lines are cut by three parallel planes, then corresponding segments are proportional $$\\\\ AE:EB=CF:FD \\\\ \\Rightarrow \\dfrac{6}{8}=\\dfrac{x}{12-x} \\\\ \\Rightarrow 72-6x=8x \\\\ \\Rightarrow 14x=72 \\\\ \\Rightarrow x=\\dfrac{72}{14} \\\\ \\therefore CF=x=5.14,FD=12-x=6.86$$","encodingFormat":"text/html"},"comment":{"@type":"Comment"}}]},{"@type":"Question","eduQuestionType":"Multiple choice","learningResourceType":"Practice problem","educationalLevel":"beginner","name":"Solid geometry Quiz 1","text":" A right prism of glass is $$2\\dfrac{1}{8}in.$$ Its right section is an equilateral triangle whose altitude is 0.866 in. Its lateral surface area is ","comment":{"@type":"Comment","text":" First calculate the altitude of the triangle and then use the formula to find the lateral surface area of a right prism."},"encodingFormat":"text/markdown","suggestedAnswer":[{"@type":"Answer","encodingFormat":"text/html","text":" 1.840 sq.in","position":0},{"@type":"Answer","encodingFormat":"text/html","text":" 3.680 sq.in","position":1},{"@type":"Answer","encodingFormat":"text/html","text":" 2.598 sq.in","position":3}],"acceptedAnswer":[{"@type":"Answer","encodingFormat":"text/html","text":" 6.375 sq.in","position":2,"answerExplanation":{"@type":"Comment","text":" The lateral surface area of a right prism is equal to the product of the height and perimeter. Altitude of equilateral triangle with side $$a$$ is $$\\dfrac{\\sqrt{3}}{2}a\\\\\\Rightarrow \\dfrac{\\sqrt{3}}{2}a=0.866 \\\\ \\Rightarrow a=1 \\\\ $$ Hence, Perimeter is $$3\\,in\\\\\\therefore$$ Lateral surface area $$=2\\dfrac{1}{8}.3=\\dfrac{17}{8}.3=6.375\\,sq.in$$","encodingFormat":"text/html"},"comment":{"@type":"Comment"}}]},{"@type":"Question","eduQuestionType":"Multiple choice","learningResourceType":"Practice problem","educationalLevel":"beginner","name":"Solid geometry Quiz 1","text":" Find the volume of a prism whose height is $$15ft$$., if each side of the triangular base is 10 in.","comment":{"@type":"Comment","text":" First find the area of the triangle and then use formula to find the volume of the triangular prism."},"encodingFormat":"text/markdown","suggestedAnswer":[{"@type":"Answer","encodingFormat":"text/html","text":" 649.5 sq.in","position":1},{"@type":"Answer","encodingFormat":"text/html","text":" 150 sq.in","position":2},{"@type":"Answer","encodingFormat":"text/html","text":" 75 sq.in","position":3}],"acceptedAnswer":[{"@type":"Answer","encodingFormat":"text/html","text":" 7794 sq.in","position":0,"answerExplanation":{"@type":"Comment","text":" $$ \\\\ $$ Given, height is $$15ft$$ and each side is $$10.in$$ $$ \\\\ $$ The volume of a triangular prism is equal to the height and base area. $$ \\\\ $$ Hence height of prism $$=15ft=180\\,in$$ $$ \\\\ $$ Altitude of base $$ =\\dfrac{\\sqrt{3}}{2}a=\\dfrac{\\sqrt{3}}{2}\\times 10=5\\sqrt{3}\\,in $$ $$ \\\\ $$ Area of base $$=\\dfrac{1}{2}\\times 10\\times 5\\sqrt{3}=25\\sqrt{3}$$ $$ \\\\ $$ $$\\therefore$$ Volume $$=25\\sqrt{3}\\times 180\\,in=7794\\,sq.\\,in$$","encodingFormat":"text/html"},"comment":{"@type":"Comment"}}]},{"@type":"Question","eduQuestionType":"Multiple choice","learningResourceType":"Practice problem","educationalLevel":"beginner","name":"Solid geometry Quiz 1","text":" Consider two similar cylinders of revolution with $$l$$ and $${l}'$$ as their lateral areas, $$t$$ and $${t}'$$ as their total areas , $$v$$ and $${v}'$$ as their volumes , $$h$$ and $${h}'$$ as their altitudes , and $$r$$ and $${r}'$$ as their radii. If $$\\dfrac{l}{{{l}'}}=\\dfrac{{{r}^{a}}}{{{{{r}'}}^{b}}}$$ and $$\\dfrac{v}{{{v}'}}=\\dfrac{{{h}^{p}}}{{{{{h}'}}^{q}}}$$ Then $$a+p = ?$$","comment":{"@type":"Comment","text":" Find the ratio of the lateral areas of similar cylinders in terms of their radii and their volumes in terms of their altitudes and then we get values of a and p."},"encodingFormat":"text/markdown","suggestedAnswer":[{"@type":"Answer","encodingFormat":"text/html","text":" 4","position":0},{"@type":"Answer","encodingFormat":"text/html","text":" 8","position":1},{"@type":"Answer","encodingFormat":"text/html","text":" 6","position":2}],"acceptedAnswer":[{"@type":"Answer","encodingFormat":"text/html","text":" 5","position":3,"answerExplanation":{"@type":"Comment","text":" If the lateral areas of similar revolution cylinders have the same radii and altitude, then LSA equals radii2; and their volumes are to each other as the cubes of their altitudes or as the cubes of their radii. Hence, $$\\dfrac{l}{{{l}'}}=\\dfrac{{{r}^{2}}}{{{{{r}'}}^{2}}}$$ and $$\\dfrac{V}{{{V}'}}=\\dfrac{{{h}^{3}}}{{{{{h}'}}^{3}}} \\\\ \\Rightarrow a=2;\\,p=3 \\\\ \\therefore a+p=5$$","encodingFormat":"text/html"},"comment":{"@type":"Comment"}}]},{"@type":"Question","eduQuestionType":"Multiple choice","learningResourceType":"Practice problem","educationalLevel":"beginner","name":"Solid geometry Quiz 1","text":" Consider two polar triangles $$ABC$$ and $${A}'{B}'{C}'$$ , the letter at the vertex of each angle denoting its value in degrees , and the small letter denoting the value of the opposite side in degrees.Then, $$ \\\\ $$
","comment":{"@type":"Comment","text":" First we find the relation between the angles of the polar triangles and then choose the correct statements from the options."},"encodingFormat":"text/markdown","suggestedAnswer":[{"@type":"Answer","encodingFormat":"text/html","text":" $$A+B={a}'+{b}'=B+C={b}'+{c}'=C+A={c}'+{a}'$$","position":0},{"@type":"Answer","encodingFormat":"text/html","text":" $$A=B=C$$","position":1},{"@type":"Answer","encodingFormat":"text/html","text":" $${a}'={b}'={c}'$$","position":3}],"acceptedAnswer":[{"@type":"Answer","encodingFormat":"text/html","text":" $$A+{a}'=B+{b}'=C+{c}'$$","position":2,"answerExplanation":{"@type":"Comment","text":" In two polar triangles, each angle of the one is the supplement of the opposite side in the other. Hence, we get $$\\\\ A+{a}'={{180}^{0}};\\,B+{b}'={{180}^{0}};\\,C+{c}'={{180}^{0}} \\\\ {A}'+a={{180}^{0}};\\,{B}'+b={{180}^{0}};\\,{C}'+c={{180}^{0}} \\\\ \\therefore A+{a}'=B+{b}'=C+{c}'$$","encodingFormat":"text/html"},"comment":{"@type":"Comment"}}]}]}