ABCD is rhombus with ∠ABC = 30°. The measure of ∠ACD is:
75∘
∠ABC = 30∘ (Given)
A rhombus is also a parallelogram.
Hence ∠BCD = 180∘ - 30∘ = 150∘ (Adjacent angles of a parallelogram are supplementary)
∵ Diagonals of rhombus bisects the angles.
∴ ∠ACD = 12 ∠BCD
= 12 × 150∘
= 75∘