May someone please help me out? Please show full steps ♡´･ᴗ･`♡

Step-by-step explanation:

METHOD 1

in centre it is split by 4, each angle is equal.

in a square angles add up to 360°

360/4=90°

∴∠DOC=90°

if you have to do more work or have toexplain more, or you dont get that way there is another method:

METHOD 2

since ABCD is a square it alladds up to 360°

so ∠A=B=C=D=90°

in triangle DOC anles add up to 180°

each diagonal cuts angleA,B,C and D in half

so in triangle DOC, ∠ODC=∠CDO=45

∠DOC=180-∠DOC-∠CDO       (or 180-(∠DOC+∠CDO)

∠DOC=180-45-45

∠DOC=90