The area of the sector with a central angle measuring 90° and radius of length 4 cm is π cm2.

A sector’s area is the fraction of the full circle’s area given by its central angle. A 90° angle is one-fourth of 360°, and a circle with radius 4 cm has area π × 4² = 16π cm². One-fourth of 16π is 4π, so the coefficient is 4; the correct choice is 4.

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