# Increase \chapter{Title} horizontal margins

I am writing my dissertation and I am requested to write the chapter titles as inverted pyramids. Because of the specific margins I have on the format I am using and because of the specific words I have in one title, I am not able to make it. How can I force the margins of one chapter title only to be a little wider?

This is my title:

\chapter{Effects of Irradiance and Ambient Temperature on a Decision-Making\\Tool for Rooftop PV Array Sizing\\ for Commercial Buildings}

• Welcome to TeX.SX! What class are you using? The standard book class typesets chapter titles ragged right, which is difficult to make inverted pyramids with. – egreg Sep 7 '18 at 21:23
• I am using a customized class from my university. The title is actually centered. – Carlo Bianchi Sep 7 '18 at 23:23
• Without some detail about the class, it's impossible to help – egreg Sep 8 '18 at 5:43
• If your university wants pyramidal chapter titles and they supply the class, then they should modify the class so that the results suit their demands. – Peter Wilson Sep 8 '18 at 17:25

Set the title inside a centred box using \makebox[\linewidth] and stack it using tabular:

\documentclass{report}

\usepackage{geometry} % Just for this example
\geometry{
paper = a3paper,
landscape,
showframe
}

\begin{document}

\chapter[ToC title]
{\makebox[\linewidth]{\begin{tabular}{ c }
Effects of Irradiance and Ambient Temperature on a Decision-Making \\
Tool for Rooftop PV Array Sizing                         \\
for Commercial Buildings
\end{tabular}}
}

\end{document}