Question

if (mangle a = mangle b) and (mangle a + mangle c = mangle d), then (mangle b + mangle c = mangle d). which property is shown? symmetric property transitive property reflexive property substitution property

Explanation:

Since \(m\angle A=m\angle B\) and \(m\angle A\) is replaced by \(m\angle B\) in \(m\angle A + m\angle C=m\angle D\), it's the substitution property.

Answer:

substitution property