等腰三角形
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<style type="text/css">
#box{
width: 0;
height: 0;
border-top: 40px solid transparent;
border-left: 40px solid transparent;
border-right: 40px solid transparent;
border-bottom: 40px solid red;
}
</style>
<body>
<div id="box">
</div>
</body>
</html>
直角三角形
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<style type="text/css">
#box{
width: 0px;
height: 0;
border-top: 0px solid transparent;
border-left: 0px solid transparent;
border-right: 100px solid transparent;
border-bottom: 40px solid red;
}
</style>
<body>
<div id="box">
</div>
</body>
</html>
梯形
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<style type="text/css">
#box{
width: 50px;
height: 0;
border-top: 40px solid transparent;
border-left: 40px solid transparent;
border-right: 40px solid transparent;
border-bottom: 40px solid red;
}
</style>
<body>
<div id="box">
</div>
</body>
</html>
单边梯形
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<style type="text/css">
#box{
width: 50px;
height: 0;
border-top: 40px solid transparent;
border-left: 40px solid transparent;
border-right: 40px solid transparent;
border-bottom: 40px solid red;
}
</style>
<body>
<div id="box">
</div>
</body>
</html>