Josh 
@heycitizen @ganbatte @amiserabilist you have your 80° and 100° angles reversed. The left triangle is 40/60/80 (180° total). So it’s 180 - 45 = 135°.
heycitizen@josh0 @ganbatte @amiserabilist lol yeah I realised and deleted the post. Early morning arithmetic on the train 😴