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You should consider helmet shape before measuring for helmet size. This is especially important if you are looking for a motorcycle helmet. There are three main types of shapes, which are long oval, intermediate oval, and round oval. The helmet shape matters for most helmet types, though it is more important for motorcycle and riding helmets. Long oval means that the shape of the head, and helmet, is longer front-to-back than side-to-side. Intermediate oval means that the shape of the helmet will be slightly longer from front-to-back than from side-to-side. This is the most common shape. A round oval shape is one that is almost equal from front-to-back as it is side-to-side. You should position it just above your eyebrows. Make sure the measuring tape lays flat against your head but doesn't pinch. It should be level all the way around. Doing this on your own is a challenge. Ask a friend or family member for help, or use a mirror to help you level the tape. If you're measuring your head circumference on your own, cross the ends of the tape on the front of your head to make reading the measurement easier. Take several measurements. The largest measurement you take is the measurement to go by. Write down this measurement so that you will remember it when it comes to choosing a helmet.

summary: Determine helmet shape. Wrap the flexible measuring tape around your head. Read the measurement off the tape.

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You can use a table, desk, or even the ground to lay out the piece of wood. Lay the wood so it's flat and even and won't wobble. Work in a safe area such as an open room or outside. Trebuchets launch projectiles that could break a window. Use a ruler or tape measure to measure 3 inches (7.6cm) from the left side of the piece of the 12in (30cm) piece of wood. Use a pencil or marker to make a line indicating the measurement. Line up the left edge of the wood with the line you marked on the horizontal wooden board. Line up the bottom edge of the verticle board with the edge of the horizontal board. Lay the square of wood flat on a surface. Use a ruler and a pencil or marker to draw a straight line from 1 corner of the square to the corner across from it. Cut along the straight line to create 2 even triangles of wood. Use a square piece of would about 12 inches (2.55.1cm) thick. Use a circular saw to cut the most even line. Place the triangle so the left and bottom edge are flush against the edges of both pieces of wood. Apply super glue to the wood where they will be covered by the triangle and press the triangle against the 2 pieces so it adheres to them. Use super glue for a stronger bond. Take 3 nails and use a hammer to nail them into the triangle at the 2 bottom corners and the top. Drive the nails into the triangle so they penetrate through the pieces of wood behind it and form a secure connection. Tap lightly and aim carefully so you don't damage the wooden boards. Lay a 12in (30cm) piece of wood flat and measure 3 inches (7.6cm) from the right end of the wood and place a mark. Then, place a 10 inches (25cm) wooden board vertically at the marked line, and glue the other triangle you cut out to the 2 pieces of wood. Drive 3 nails into the triangle. You need 2 frame pieces to form your trebuchet, but they need to be mirror images so they align correctly.

summary: Lay a 12in (30cm) piece of wood horizontally on a surface. Measure 3 inches (7.6cm) from the left end and mark a line. Place a 10in (25cm) piece of wood vertically at the marked line. Cut 2 triangles out of a 5 by 5in (13 by 13cm) square of wood. Glue 1 of the triangles onto where the 2 pieces of wood meet. Nail 1 inch (2.5cm) nails through the triangle into the wood. Make a mirror image of the upright so you have 2 of them.

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The DVD has to be blank (e.g., brand-new) and logo-side-up for this to work. The CD tray must be able to burn DVDs. You can tell whether or not your computer's CD tray can burn DVDs by looking for the "DVD" logo on or near the CD tray. Click the Windows logo in the bottom-left corner of the screen. Click the folder icon in the lower-left side of the Start window. Click the folder into which you downloaded your movie. Click your movie to select it. It's a tab in the upper-left side of the window. Doing so prompts a toolbar to appear below the top of the window. You'll find this in the "Send" section that's on the left side of the toolbar. A window will open. It's at the top of the window. Your movie will begin burning onto your DVD. This process will take anywhere from several minutes to an hour or more depending on the size of the movie and your computer's burn speed. It's at the bottom of the window. After you click Finish, you can eject your DVD from your computer and test it in a DVD player of your choosing.
summary: Insert a blank DVD-R into your computer's CD tray. Open Start . Open File Explorer . Select a file location. Select your movie. Click Share. Click Burn to disc. Click Burn. Click Finish when prompted.