Concave means rounded inward.

Concave means rounded inward.

• A. Flattened outward
• B. Outward bulging
• C. A curved line
• D. Rounded inward

Answer: (D)

Concave describes a surface or line that curves inward, creating an indentation. When something is concave, its boundary bends toward the interior, so “rounded inward” matches the idea exactly. The other descriptions describe outward features or are too vague: flattened outward suggests no inward curve, outward bulging describes the opposite (convex), and a curved line is just generic curvature without indicating inward versus outward. So rounded inward is the precise way to express concave.

Concave describes a surface or line that curves inward, creating an indentation. When something is concave, its boundary bends toward the interior, so “rounded inward” matches the idea exactly. The other descriptions describe outward features or are too vague: flattened outward suggests no inward curve, outward bulging describes the opposite (convex), and a curved line is just generic curvature without indicating inward versus outward. So rounded inward is the precise way to express concave.