// Numbas version: exam_results_page_options {"name": "Q1 Circle mensuration problems", "extensions": [], "custom_part_types": [], "resources": [["question-resources/circle-sector-area.gif", "/srv/numbas/media/question-resources/circle-sector-area.gif"], ["question-resources/circle-segment-area.gif", "/srv/numbas/media/question-resources/circle-segment-area.gif"]], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"functions": {"circle": {"definition": "\n var c = document.createElement('canvas');\n $(c).attr('width',600).attr('height',450);\n var context = c.getContext('2d');\n \n //fill in rectangle with a light shade\n context.fillStyle = '#eee';\n context.beginPath();\n context.arc(200, 200, 150, 50, Math.PI*2, true); \n context.closePath();\n context.fill();\n \n //draw labels\n context.fillStyle = '#000';\n context.font = '20px sans-serif';\n var wstring = 'Perimeter ='+ p +'m';\n var tw = context.measureText(wstring).width;\n// console.log(tw);\n context.fillText(wstring,60,38);\n \n var hstring = 'r';\n var hw = context.measureText(hstring).width;\n context.save();\n context.translate(30,200);\n context.rotate(-2*Math.PI);\n context.fillText(hstring,70,-5);\n\n var hstring = '____________';\n var hw = context.measureText(hstring).width;\n context.save();\n context.translate(30,200);\n context.rotate(2*Math.PI);\n context.fillText(hstring,-10,-200);\n \n return c;\n ", "type": "html", "language": "javascript", "parameters": [["p", "number"]]}, "ang": {"definition": "var c = document.createElement('canvas');\n$(c).attr('width',300).attr('height',300);\nvar ctx = c.getContext('2d');\n\nvar angle = Math.PI *((a-(Math.PI/2))/180); // == 45 degrees\nvar cx = 150;\nvar cy = 150;\nvar radius = 100;\n\nangle-=Math.PI/2;\nctx.lineWidth = 2;\nctx.strokeStyle = 'red';\n\n// draw the red line at the desired angle\nctx.beginPath();\nctx.moveTo(cx, cy);\nctx.arc(cx, cy, radius, angle, angle);\nctx.stroke();\n\n// draw the bulls-eyed circle\nctx.beginPath();\nctx.strokeStyle = 'black';\nctx.arc(cx, cy, radius, 0, Math.PI * 2);\nctx.moveTo(cx - radius, cy);\nctx.lineTo(cx + radius, cy);\nctx.moveTo(cx, cy - radius);\nctx.lineTo(cx, cy + radius);\nctx.stroke();\n\n\n\nreturn c;", "type": "html", "language": "javascript", "parameters": [["a", "number"]]}, "circle1": {"definition": "\n var c = document.createElement('canvas');\n $(c).attr('width',600).attr('height',450);\n var context = c.getContext('2d');\n \n //fill in rectangle with a light shade\n context.fillStyle = '#eee';\n context.beginPath();\n context.arc(200, 200, 150, 50, Math.PI*2, true); \n context.closePath();\n context.fill();\n \n //draw labels\n context.fillStyle = '#000';\n context.font = '20px sans-serif';\n var wstring = 'Area ='+ p +'m^2';\n var tw = context.measureText(wstring).width;\n// console.log(tw);\n context.fillText(wstring,60,38);\n \n var hstring = 'r';\n var hw = context.measureText(hstring).width;\n context.save();\n context.translate(30,200);\n context.rotate(-2*Math.PI);\n context.fillText(hstring,70,-5);\n\n var hstring = '____________';\n var hw = context.measureText(hstring).width;\n context.save();\n context.translate(30,200);\n context.rotate(2*Math.PI);\n context.fillText(hstring,-10,-200);\n \n return c;\n ", "type": "html", "language": "javascript", "parameters": [["p", "number"]]}}, "ungrouped_variables": ["r", "area1", "ans1", "area12", "per2", "per22", "ans2", "ans3", "ans4", "sect", "rad", "ans5", "rds", "ans6", "sect1", "ans7", "ans8", "area5", "circ6"], "name": "Q1 Circle mensuration problems", "tags": ["area of a circle", "area of a sector", "canvas", "Circle", "circle", "function", "graphic", "Perimeter", "perimeter", "rebelmaths", "Sector", "sector", "teame"], "preamble": {"css": "", "js": ""}, "advice": "

part 1

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Formula for perimeter of circle.

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Perimeter = $2 \\times \\pi \\times r$

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radius(r) =  $\\frac{\\text{Perimeter}}{2 \\times pi} = \\var{ans7}m$

\n

\n

part 2

\n

Formula for area of circle.

\n

Area = $\\pi r^2$

\n

radius(r)= $\\sqrt\\frac{(\\text{area})}{pi} = \\var{ans8}m$

\n

\n

part 3

\n

Formula for area of circle.

\n

Area = $\\pi r^2$

\n

radius(r)= $\\sqrt\\frac{(\\text{area})}{pi}$

\n

\n

Formula for perimeter of circle.

\n

Perimeter = $2 \\times \\pi \\times r$

\n

$2 \\times \\pi \\times r[0] = \\var{ans1}m$

\n

\n

Part 4

\n

Formula for perimeter of circle.

\n

Perimeter = $2 \\times \\pi \\times r$

\n

Therefore;

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radius(r)= $\\frac{(\\text{perimter})}{2 \\times \\pi}$

\n

$\\frac{\\var{per22}}{2 \\times \\pi} = \\var{r[1]}m$

\n

\n

Formula for area of circle.

\n

Area = $\\pi r^2$

\n

$\\pi \\times \\var{r[1]}^2 = \\var{ans2}m^2$

\n

\n

Part 5

\n

$\\frac{\\pi \\times \\var{r[2]}}{2} + 2 \\times \\var{r[2]} = \\var{ans3}$

\n

$\\frac{\\pi \\times \\var{r[2]}^2}{4} = \\var{ans4}$

\n

\n

Part 6

\n

\n

where theta is in radians.

\n

$\\frac{\\var{rds}}{2} \\times \\var{rad}^2= \\var{ans5}$

\n

$\\frac{1}{2} \\times (\\var{rds} - sin(\\var{rds})) \\times \\var{rad}^2= \\var{ans6}$

\n

", "rulesets": {}, "parts": [{"prompt": "

{circle(circ6)}

\n

The length of the circumference of a circle is $\\var{circ6}m$. Find the length of the radius of the circle.

\n

[[0]] $m$

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{circle1(area5)}

\n

The area of a circle is $\\var{area5}m^2$. Find the radius of the circle?

\n

[[0]]m

\n

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{circle1(area12)}

\n

This circle has an area of $\\var{area12}m^2$. Calculate the perimeter of this circle?

\n

[[0]]m

\n

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First you need to find the radius of this circle.

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{circle(per22)}

\n

Calculate the area of a circle which has a perimeter of $\\var{per22}m^2$.

\n

[[0]] $m^2$

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First you need to find the radius of this circle.

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A steel plate is in the shape of a quadrant of a circle and has a radius of $\\var{r[2]}$m. Calculate the perimeter of this plate and the area of the segment.

\n

Perimeter = [[0]]m

\n

Area = [[1]]$m^2$

", "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "steps": [{"prompt": "

Remember the formula for the area of a sector uses radian measure for the angle.

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{ang(sect1)}

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A sector of a circle makes an angle of $\\var{sect}$ degrees at the centre and has a radius of $\\var{rad}cm$. Calculate the area of the sector and the area of the segment.

\n

The angle is the obtuse angle between the positive x-axis line, (3 o'clock point) and the red line, in an anti-clockwise motion.

\n

Area of sector = [[0]]$cm^2$

\n

Area of segment = [[1]]$cm^2$

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The following diagrams should help to explain the question.

\n

\n

where theta is in radians.

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Solve the following to two decimal places.

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Circumference and area of a circle

\n

rebelmaths

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