Question

1n the given figure, the diagonals of a rhombus ABCD intersect at O.
If ∠ADC = 120°, OC = 3 cm and OD = 4 cm, find
(i) ∠OAD (ii) side AB (iii) perimeter of rhombus ABCD. plz help and don't spam

Answer 1

Answer:

Find ∠OAD

∠OAD = ∠OCD (Isosceles triangle)

∠OAD = (180 - 120) ÷ 2

∠OAD = 30º

Find side ∠DAB:

∠ADC + ∠DAB = 180 (opposite sides of a rhombus)

120 +  ∠DAB  = 180

∠DAB = 180 - 120 = 60º

FInd DB:

BD = OD = 6 cm

DB = 6 x 2 = 12 cm