SOURCE

<div class="triangle div1"></div>
<div class="triangle div2"></div>
<div class="triangle div3"></div>
<div class="triangle div4"></div>
<div class="triangle div5"></div>

.triangle{
    width: 0;
    height: 0;
    margin-bottom:15px;
}
.div1{
    border:50px solid rgba(137, 207, 235, 0.10);
    border-bottom: 50px solid skyblue
}
.div2{
    border:90px solid rgba(137, 207, 235, 0.10);
    border-bottom: 50px solid skyblue
}

.div3{
    border:20px solid rgba(137, 207, 235, 0.10);
    border-bottom: 50px solid skyblue
}
.div4{
    border-left:150px solid rgba(137, 207, 235, 0.10);
    border-bottom: 50px solid skyblue
}

.div5{
    border-right:80px solid rgba(137, 207, 235, 0.10);
    border-bottom: 150px solid skyblue
}