P.ex.
How to connect your iPad to a projector in 3 different ways (businessinsider.nl)
Your projector likely has a VGA port or HDMI port, and you will need to get an adapter to connect it to your iPad. HDMI is usually the way to go, as it supports both video and audio, while VGA doesn’t support sound.
Fortunately, it’s easy to find adapters that have both VGA and HDMI inputs as well as adapters for one or the other. Just keep in mind that you will also need a VGA or HDMI cable to run between the adapter and the projector.
You should also double check your iPad port – most iPads have lightning ports (so you’d want a lightning adapter), but recent iPad Pro models have replaced the lightning port with USB-C, so you’d want a USB-C adapter for these iPads.
How to Connect an iPad to a Projector (lifewire.com)
= Ipad - lightning port - lightning to Hdmi adapter - Hdmi cable - projector
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Est-ce que mon chromecast branché sur le HDMI du projecteur suffirait ?
En principe oui
Does Google Chromecast Work with a Projector? (hometheateracademy.com)