| Answer | Crossword Clue |
|---|---|
| OST | 90 degrees, in Bonn |
| ACUTE | Less than 90 degrees, in geometry |
| ANGLE | Each one in a square is 90 degrees |
| complement | The amount in degrees by which a given angle is less than 90░ |
| complements | The amount in degrees by which a given angle is less than 90░ |
| backscatter | the deflection of radiation or particles by scattering through angles greater than 90 degrees with reference to the original direction of travel / to scatter in this way |
