In SharePoint 2010 (and later) it is possible to display powerpoint presentations / slides inside of a Page Viewer Web Part if you have the Office Web Apps installed on your SharePoint installation.
- Enable Office Web Apps in the Site Collection Features administration
- Load your powerpoint into a document library somewhere on your site
- Inside of the Edit Control Block (a fancy SharePoint term for the
dropdown menu that appears next to a list item when you select the
expand arrow in its title -- see screenshot at bottom of this answer) select "View in Browser"
- On that page select "open in popup" at the top right of the page (this may also appear as 'Embed' in some systems)
- Copy the URL from that pop-up page, depending on your browser you may have to right click the page and select "properties" to see the full URL
- On the page you want to display the slide, edit the page and from the ribbon select Insert => WebPart => Media and Content => Page Viewer => Add
- open the tool pane as the webpart will prompt you (do save the page if prompted)
- in the "Link" box of the WebPart properties paste in the link to the pop-up page you viewed earlier with your powerpoint slide and select "Ok"
And your slide should appear on the page inside of that page viewer web part.
This technique has the advantage of updating the display automatically if you update the powerpoint file, but you might also just consider exporting the slide you're interested in as a picture and posting it into something like a content editor or the wiki edit area of the page you're working on.
Here is a walkthrough with some pictures of the page viewer technique on the nothingbutsharepoint site: http://www.nothingbutsharepoint.com/2011/12/07/display-a-powerpoint-document-in-sharepoint-via-the-page-viewer-web-part-aspx/
And here is a screenshot of the Edit Control Block (or ECB):
If you're having a hard time finding the "View in Browser" command, check out video number 6 on this page: https://support.office.com/en-au/article/SharePoint-document-libraries-I-An-introduction-a5a82359-bbde-46c8-9a0e-1a4628cc6603
And welcome to working with SharePoint!