How do I responsively center text inside of a <div> - html

Question

I have a <div> that contains three <div>s.
In each of those <div> elements is a <p> element with text and 2 nested elements to make a radial progress bar. What I need is to put the text in the middle of the circles, and do it responsively using pure CSS. I need something like this:
The code has flaws, like that <p> inside of a <span> but I am fixing it in the new version with the help you guys provide.
.radius-container div {
-webkit-box-flex: 1;
-ms-flex: 1;
flex: 1;
}
.radius-container div:first-child {
margin-right: 1%;
}
.radius {
padding-top: 11em;
height: 30em;
text-align: center;
border: 1px solid #858280;
display: block;
border-radius: 50%;
width: 100%;
}
.radius3 {
position: relative;
padding-top: 10%;
height: 15em;
width: 50%;
text-align: center;
border: 1px solid #858280;
border-left: 0;
border-bottom: 0;
border-top-right-radius: 100%;
display: block;
margin-left: 15em;
}
.radius3 p {
position: absolute;
right: 50%;
top: 65%;
}
<div class="radius-container">
<div><span class="radius"><p>SERBIAN<br>100%</p></span></div>
<div><span class="radius"><p>ENGLISH<br>100%</p></span></div>
<div><span class="radius3"><p>GERMAN<br>25%</p></span></div>
</div>
See also this jsFiddle

Answer 1

After researching for long time for this issue, I found an generic solution which solves this kind of requeriments. I am proud of it, simple and elegant :)
.center-element{
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
}
Hoping it helps, any doubt let me know. Cheers mate :)

Answer 2

This code might help you.
.innerDiv {
height: 100px;
width: 100px;
display: table-cell;
text-align: center;
vertical-align: middle;
border-radius: 50%;
}

Answer 3

You can make a div with a border-radius to 50%. After, you can use the flex display to center verticaly and horizontaly.
html
div {
display: flex;
flex-direction: row;
align-items: center;
justify-content: center;
}
div div {
display: inline-flex;
flex-direction: column;
width: 31%;
margin: 1%;
border-radius: 50%;
border: 1px solid #999;
align-items: center;
justify-content: center;
}
div div span {
text-align: center;
color: #999;
}
<div>
<div><span>Serbian</span><span>100%</span>
</div>
<div><span>Serbian</span><span>50%</span>
</div>
<div><span>Serbian</span><span>25%</span>
</div>
</div>