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Basic trigonometry question, students are asked to find the diameter of a circular tunnel given distance from edge of a roadway to centre top of tunnel (randomised) and angle from edge of road to centre top of tunnel (randomised).
", "licence": "Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International"}, "statement": "", "advice": "Let \\(D\\) be the point at the intersection of \\(AC\\) and \\(BZ\\). We have that angle \\(BDA=90^\\circ\\) and hence angle \\(ABD=\\var{90-A}^\\circ\\).
\nSince angle \\(BAZ=90^\\circ\\) we have \\[\\cos\\var{90-A}^\\circ=\\frac{\\var{d}}{BZ}\\] and hence \\begin{align}BZ&=\\frac{\\var{d}}{\\cos\\var{90-A}^\\circ}\\\\&\\approx\\var{precround(d/sin(pi*A/180),2)}\\end{align}
\nHence the diameter of the tunnel is approximately \\(\\var{precround(d/sin(pi*A/180),2)}\\) metres.
", "rulesets": {}, "extensions": [], "builtin_constants": {"e": true, "pi,\u03c0": true, "i": true}, "constants": [], "variables": {"d": {"name": "d", "group": "Ungrouped variables", "definition": "random(4..9)", "description": "Distance from A to B in m in diagram, random integer from 4 to 9
", "templateType": "anything", "can_override": false}, "A": {"name": "A", "group": "Ungrouped variables", "definition": "random(45..80 #5)", "description": "Angle BAC in diagram in degrees, random 45 to 80 in steps of 5.
", "templateType": "anything", "can_override": false}}, "variablesTest": {"condition": "", "maxRuns": 100}, "ungrouped_variables": ["d", "A"], "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 a circular car tunnel with \\(AB=\\var{d}\\) metres and angle \\(BAC=\\var{A}^\\circ\\). Assume that angle \\(BAZ=\\) angle \\(BCZ=90^\\circ\\) and that \\(BZ\\) is perpendicular to \\(AC\\). Find the diameter, \\(BZ\\), of the tunnel. Write the diameter in the box below and show your full working on your working paper.
\nDiameter = [[0]] m (give your answer correct to 2 decimal places)
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