A twin bed is 39" x 75". An X-large twin is 39" x 80". You'd want your afghan to be a bit wider since there will be a body lifting it up and you may want it to go a bit over the sides of the bed. The length is flexible since you would only need the afghan to cover the part of the bed below the pillow.
it is best to use an H or I size hook
yes you can but you will need more yarn as you are going to need more rows to make the same size item .. The width will not be effected at all .. if you are making a blanket it is easy just continue till same length .. if you are making a garment you will have to adjust the pattern for the height differences .. for example they may say you need 20 rows for an armhole and you may need 28 rows ..
Crochet needles, going on the numbered U.S. system range from one to ten in size.
For yarn, use an "E" or an "F".
that would be a size P crochet hook
Take two pieces of fleece, whatever size you wish to make the blanket but make sure they are both the same size. Cut slits on the edges of the blanket about an inch long and keep doing that but give about half of an inch to an inch of space between each cut. do that around the whole blanket then tie all the slits together. Its very easy once you get started!
This varies with the yarn, the hook size and the tension. You have to make a sample, count and measure.
Your answer depends on the size of the crochet needle you want to use. First, crochet a gauge, so that you have the basic information you need to calculate your raw material requirements.
Both techniques differ in the tool used. Knitting uses needles which hold "rows" of live stitches, whereas traditional crochet uses a single hook for the one live stitch. The resulting fabric is different in weight and overall appearance. Crochet fabric is thicker and stronger than knitted fabric, even using the same yarn and same size hook/needles. The difference comes from the fact that even the simplest crochet stitch is made of 2 loops, wrapped around one or two strands of yarn, and knitted stitches are a single loop in a single previous loop (single strand of yarn).
A King size blanket is 108 x 90 inches
In the US, knitting needle sizes are in numbers; crochet hooks use both numbers and letters.
While crochet enthusiasts enjoy making clothing and home decor items from patterns, even a beginner can increase her level of creativity with crocheted pictures of loved ones, a child's favorite characters or beloved pets. Use crocheted pictures on child or adult tops, decorate a child's bedspread or favorite blanket, or frame the finished picture as a wall hanging. This beginner project uses the single crochet stitch throughout the entire picture. Single crochet is the first stitch that novices learn, and it presents an attractive finished piece. If you want to crochet a picture wall hanging, you might need to add more background rows to fit the size display frame you have chosen. After choosing a favorite photo, upload it to your computer. Put graph paper in the printer and re-size the photo to your preferred size. Use color ink when printing. To crochet the photo, start by counting the number of blocks at the widest and longest rows. Add a border of three or more rows depending on your desired finished size. Single crochet the width of one block on the graph paper. The number of stitches per block varies with the type of yarn and the way that you crochet. Some people make tight crochet stitches while others make loose stitches. Once you know how many stitches to make per block on the graph paper, you can begin this pleasurable and creative endeavor. An important point for beginners to remember is to make even stitches. If some areas are loosely crocheted but other sections are of a different gauge, then your finished work will look lopsided. Add one extra single crochet stitch as the end of each row for turning your work. To use more than one color in a row, carry strands of the other colors on top of the just completed row of crochet stitches. As you crochet, these extra colors will be blended into the work but not seen. When you need to change colors, start with the new color in the previous stitch at the final yarn-over.