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Students are given two angles and the length of the side between them, they are asked to find the length of the side opposite angle A. Can be completed with the ine rule.
", "licence": "Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International"}, "statement": "", "advice": "Using the fact that the angle sum of a triangle is \\(180^\\circ\\) we can find the angle at \\(C\\) to be \\begin{align} C&=180^\\circ -\\var{A}^\\circ -\\var{B}^\\circ\\\\&=\\var{180-A-B}^\\circ\\end{align}
\nNow given that \\(AB=\\var{d}\\) mm and using the sine rule we have \\begin{align}\\frac{a}{\\sin A}&=\\frac{c}{\\sin C}\\\\\\frac{a}{\\sin \\var{A}}&=\\frac{\\var{d}}{\\sin \\var{180-A-B}}\\\\a&=\\frac{\\var{d}\\sin \\var{A}}{\\sin \\var{180-A-B}}\\\\&\\approx\\var{d*sin(pi*A/180)/sin(pi*(180-A-B)/180)}\\end{align}
\nHence the length \\(BC\\) is \\(\\var{precround(d*sin(pi*A/180)/sin(pi*(180-A-B)/180),0)}\\) mm to the nearest millimetre.
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", "templateType": "anything", "can_override": false}, "A": {"name": "A", "group": "Ungrouped variables", "definition": "random(100..120)", "description": "Size of angle A in triangle in degrees
", "templateType": "anything", "can_override": false}, "B": {"name": "B", "group": "Ungrouped variables", "definition": "random(20..50)", "description": "Size of angle B in triangle in degrees
", "templateType": "anything", "can_override": false}}, "variablesTest": {"condition": "", "maxRuns": 100}, "ungrouped_variables": ["d", "A", "B"], "variable_groups": [], "functions": {}, "preamble": {"js": "", "css": ""}, "parts": [{"type": "gapfill", "useCustomName": false, "customName": "", "marks": 0, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "The diagram below shows part of a car window with angle \\(A=\\var{A}^\\circ\\), angle \\(B=\\var{B}^\\circ\\) and length \\(AB=\\var{d}\\) mm. Find the length of \\(BC\\). Give your answer correct to the nearest mm in the box below and show full working on your handwritten notes.
\n\\(BC=\\)[[0]] mm
\n