What day was the protractor invented?
The first protractor was invented by Joseph Huddard in 1801.
OR
The Protractor was invented by Thomas Blundeville (c1522 -1606)
of Newton Flotman in Norfolk, England in 1589. His work, 'A Brief
Description of Universal Maps and Cards' published in 1589,
describes the design and use of a device he calls 'The Flie' and
includes a drawing of a semi-circle divided into segments - he
describes its use for determining angles during navigation.