In one sentence, describe what the following article is about: Smiling is the easiest way to show someone you’re interested. If you see him looking at you, give him a quick smile. If he’s thinking about kissing you, this might encourage him to move closer to you. Eye contact is a great way to flirt, since it creates an instant connection between two people. Flirt with your eyes by looking at him then looking away, then looking back for a longer gaze. When people are feeling flirtatious, they often signal this unconsciously by playing with their hair or touching their face. Send this signal intentionally by resting your hand on your cheek, wrapping a piece of hair around your fingers, or lightly touching your throat. This is especially effective if you’re talking about something you’re passionate about, since it seems like a very natural movement. If he smiles or leans towards you, you can leave your hand where it is. If he seems uncomfortable with the touch, pull your hand away. Chances are that he’s just as nervous as you are, so boost his confidence by laughing at his jokes or listening intently to his stories. Be sincere, though, since he’ll be able to pick up on fake laughter.
Summary: Smile at him. Look into his eyes flirtatiously. Touch your face or twirl your hair around your fingers. Rest your hand on his arm while you’re talking to him. Laugh at his jokes.

Ratios can be reduced and simplified like fractions by removing any common factors of the terms in the ratio. To reduce a ratio, divide all the terms in the ratio by the common factors they share until no common factor exists. However, when doing this, it's important not to lose sight of the original quantities that led to the ratio in the first place.  In the classroom example above, 5 girls to 10 boys (5 : 10), both sides of the ratio have a factor of 5. Divide both sides by 5 (the greatest common factor) to get  1 girl to 2 boys (or 1 : 2). However, we should keep the original quantities in mind, even when using this reduced ratio. There are not 3 total students in the class, but 15. The reduced ratio just compares the relationship between the number of boys and girls. There are 2 boys for every girl, not exactly 2 boys and 1 girl. Some ratios cannot be reduced. For example, 3 : 56 cannot be reduced because the two numbers share no common factors - 3 is a prime number, and 56 is not divisible by 3. One common type of problem that employs ratios may involve using ratios to scale up or down the two numbers in proportion to each other. Multiplying or dividing all terms in a ratio by the same number creates a ratio with the same proportions as the original, so, to scale your ratio, multiply or divide through the ratio by the scaling factor.  For example, a baker needs to triple the size of a cake recipe. If the normal ratio of flour to sugar is 2 to 1 (2 : 1), then both numbers must be increased by a factor of three. The appropriate quantities for the recipe are now 6 cups of flour to 3 cups of sugar (6 : 3). The same process can be reversed. If the baker needed only one-half of the normal recipe, both quantities could be multiplied by 1/2 (or divided by two). The result would be 1 cup of flour to 1/2 (0.5) cup of sugar. Another common type of problem that incorporates ratios asks you to find an unknown variable in one ratio, given the other number in that ratio and a second ratio that is equivalent to the first. The principle of cross multiplication makes solving these problems fairly simple. Write each ratio in its fractional form, then set the two ratios equal to each other and cross multiply to solve. For example, let's say we have a small group of students containing 2 boys and 5 girls. If we were to maintain this proportion of boys to girls, how many boys would be in a class that contained 20 girls? To solve, first, let's make two ratios, one with our unknown variables: 2 boys : 5 girls = x boys : 20 girls. If we convert these ratios to their fraction forms, we get 2/5 and x/20. If you cross multiply, you are left with 5x=40, and you can solve by dividing both figures by 5. The final solution is x=8.
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One-sentence summary -- Reduce a ratio to its simplest form. Use multiplication or division to "scale" ratios. Find unknown variables when given two equivalent ratios.

Problem: Article: Double-clicking the PDF will accomplish this if Adobe Acrobat is your computer's default PDF reader. If Adobe Acrobat isn't your default PDF reader, do the following:   Windows — Right-click the PDF file, select Open with, and click Adobe Acrobat.  Mac — Click the PDF, click File, select Open With, and click Adobe Acrobat. It's a menu in the upper-left side of the screen. A drop-down menu will appear. On Windows, you may first have to click the View tab at the top of the Acrobat window and then select Tools. It's near the top of the page in the "Create & Edit" section. This opens the editing toolbar and additional options at the top of the window. It's next to the icon of a chain in the editing toolbar at the top of the page. This opens a drop-down menu. It's the first option at the top of the drop-down menu. Doing so turns your mouse cursor into a crosshairs icon. Click and drag your mouse cursor over and down across the text or the object that you want to use as a hyperlink, then release the mouse button. Doing so will open a window. For example, if you wanted to add a link to the words "Click here:", you would drag from the top-left side of the "C" in "Click" to the bottom-right side of the "e" in "here". Select the "Link Type" drop-down box and choose whether or not you want the clickable rectangle you just selected to be visible or invisible. If you choose a visible link, you can select:   Line Style: Set the type of outline you want the box to have; solid, dashed, or underlined.  Color: Choose what color you want the outline to be.  Highlight Style: Set what you want the linked box to do when clicked (only applies to certain PDF viewers). This will depend on the type of link you want to add:   Go to a Page View: Links to another page in the PDF. Click Next, go to the page you want to select, then click Set Link.  Open a File: Select a file from your computer, click Select, fill out any necessary options if prompted, and click OK.  Open a Web Page: Enter the address for the website you want to link (making sure to use the website's full address, including "https://") then click Enter. Press Ctrl+S (Windows) or ⌘ Command+S (Mac) to save your changes to the PDF. The linked item should now be active as a hyperlink, meaning that you can click it to open the link.
Summary:
Open the PDF in Adobe Acrobat. Click Tools. Select Edit PDF. Select Link. Click Add/Edit Web or Document Link. Create a link. Choose the link's appearance. Select the link's action. Save your PDF.