What is C3H4's shape called? Is it trigonal planar

${C}_{3} {H}_{4}$ has 2 degrees of unsaturation. A degree of unsaturation represents an unsaturated bond or a ring.
So a formula of ${C}_{3} {H}_{4}$ could be cyclopropene, propyne, ${H}_{3} C - C \equiv C H$, or allene, ${H}_{2} C = C = C {H}_{2}$. You don't know what it is in the absence of further information.