Match the reasons with the statements in the proof if the last line of the proof would be 6. ∠1 and ∠7 are supplementary by definition. given: s || t prove: 1, 7 are supplementary

Given : s||t

Exterior sides in opposite rays : ∠5 and ∠7 are supplementary

Definition of supplementary angles : m∠5 + m∠7 = 180°

If lines are ||, corresponding angles are equal : m∠1 = m∠5

Substitution : m∠1 + m∠7 = 180°

option c (nickel) is not found in earth's crust. the earth's crust basically contains eight (8) elements namely: oxygen, silicon, aluminum, iron, calcium, sodium, potassium and magnesium (listed in order of abundance).