In Inkscape, go to File > Document Properties, and click on the Colour tab. From the Available Colour Profiles dropdown, choose the sRGB colour profile. Then export the PNG. This will ensure the image is saved with the correct colour profile. This colour profile is the one used for colour reproduction on the web, and most software can recognise it.

Now you can insert the PNG into your PowerPoint document. I don't use PowerPoint, but a similar program called LibreOffice Impress. Here's a screenshot showing the correct colour using an on-screen colour picker. As you can see, the colour is 229,20,10 (#E5140A).

Click on this image to enlarge

In Inkscape, go to File > Document Properties, and click on the Colour tab. From the Available Colour Profiles dropdown, choose the sRGB colour profile. Then export the PNG. This will ensure the image is saved with the correct colour profile. This colour profile is the one used for colour reproduction on the web, and most software can recognise it.

Now you can insert the PNG into your PowerPoint document. I don't use PowerPoint, but a similar program called LibreOffice Impress. Here's a screenshot showing the correct colour of a graphic I made in Inkscape, then imported into Impress, using an on-screen colour picker. As you can see, the colour is 229,20,10 (#E5140A).

Click on this image to enlarge