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Triangles

Area of a triangle
Angles of a triangle
Measuring angles
Measuring length
Coordinates
Isosceles triangles
Right-angled triangles
Pythagoras' Theorem
Trig.

P16: Triangles

 An interactive resource which enables the user to create triangles. Use this resource for: area of a triangle, angles of a triangle, measuring angles, measuring length, coordinates, isosceles triangles, right-angled triangles, Pythagoras' Theorem, Trig. Best viewed in full-screen mode: if you are using Internet Explorer press F11 The buttons (numbered top to bottom) 1. Show/hide the area 2. Show/hide the length of each side 3. Show or hide the size of each angle 4. Snap to a grid (mm, 5mm or 1cm) 5. Stick to a line: the point will try to stick to aline when dragged. 1. Coordinates and labels, click once to show labels, again to show coordinates, again to hide coordinates. 2. Show/hide axes 3. show/hide protractor 4. Show/hide ruler 5. Show hide/rectangle 6. Show/hide cm grid 7. Show/hide mm grid If the protractor or ruler are shown then an extra set of buttons is shown: 1. Rotate ruler or protractor clockwise 2. Rotate ruler or protractor anti-clockwise 3. Rotate 90 degrees 4. Zoom (protractor only) The protractor and ruler can both be dragged about.

 Circles: pi P1: Heading towards pi An interactive resource which shows regular polygons with an increasing number of sides. The perimeter, length of a diagonal and the perimeter/diagonal is shown. Use the sliders to change the number of sides and the size of the polygon.

 Bearings Gunk the punk! Gunk the punk! Interactive resources which involve using three-figure bearings. The aim is to fire the pink gunk at the punk. Use the number pad to input the required bearing: it must be a three-figure bearing, ie 023 not 23. The bearing is shown at the top of the screen. It is not possible to enter a number greater than 360. Use the slider to determine the speed then click on 'go'. Practise gunking the punk The punk will appear in a different place after he has been gunked. P2: Gunk the punk 1: the north and direction arrows are displayed. P3: Gunk the punk 2: expert gunkers only! The north and direction arrows are not displayed. P4: Gunk the punk game How many times can you gunk the punk in 5 minutes? The time you are allowed to take aim will decrease the more times you gunk the punk. Show/hide: direction lines bearing protractor P5: Air traffic control A radar screen shows the position of 8 planes. The bearing of each plane from the air traffic control centre can be displayed. Click on a plane to show its bearing. Click on either side of a plane to show the direction line. All the direction lines and bearings can be shown or hidden by clicking on the buttons (see left). A protractor can also be displayed. Please note: the direction in which the plane is flying is not shown.

Angle and rotation, length

A screenshot of the activity

Measure length

Estimate, draw and measure angles

P17: Target Angle
Use this resource for estimating and measuring angles up to 180 degrees.

A target angle is generated randomly. Can you make the target angle?
First use the slider to construct the angle.
Click the 'OK' to have your angle measured.
Click the 'next' button for another angle or click 'start again' to reset your scores.

P6: Place in order of size a set of angles each less than 180 degrees.

P7: Say whether an angle is acute or obtuse and estimate the size to the nearest 5 degrees.

Measuring an angle

P8: Measure an angle. An angle is randomly generated; keep clicking until you are happy with the angle. The angle can be estimated or measured. Move the angle by dragging its 'corner'. Reveal the protractor and move it into position then rotate it to fit over the angle. The angle can also be rotated.

 Show/hide protractor Rotate buttons Rotate the angle Zoom button

Measuring length with a ruler

P9: Measure the length of each of three lines. Drag the ruler into position.

P10: Measure the length of each side of a quadrilateral. A quadrilateral is randomly generated; keep clicking until you are happy with the quadrilateral. Drag the ruler to measure one side of the quadrilateral. Use the rotate buttons to line up the ruler and the side. Use the zoom button to zoom in or out. The quadrilateral can be moved by dragging the top left corner.

 Area and perimeter Area and perimeter of a rectangle P18: A problem-solving activity The length and width of a rectangle are generated, the area and perimeter are worked out. Click inside the blue rectangles to hide or show the numbers. Show the length and width, can you work out the area and perimeter of the rectangle? Click on 'change' to generate two more numbers. Hide the area and perimeter, can you work out the length and width of the rectangle? Hide the length and area, can you work out the width and perimeter? P11: Work out the area and perimeter of rectangles. P12: Work out the shaded area P13: Work out the area of triangles on square dotty paper. P14: Work out the area of quadrilaterals on square dotty paper. P15: Work out the area of parallelograms and trapezia on square dotty paper.