PRINCIPIA · THEOREM

Complements of the same angle are equal

Dependencies: Protractor axiom (angles can be treated as real numbers).

Statement

Let α\alpha and β\beta both be complementary to the same angle γ\gamma:

α+γ=90,β+γ=90.\alpha + \gamma = 90^{\circ},\qquad \beta + \gamma = 90^{\circ}.

Then α=β\alpha = \beta.

Two right angles are split into \alpha + \gamma and \beta + \gamma, sharing the same \gamma ⇒ \alpha = \beta

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