The area on a map is measured by _________.

Correct option is A

Introduction
A Planimeter is an instrument specifically designed to measure the area of an arbitrary two-dimensional shape on a flat surface, such as the area of a region drawn on a map. The operator traces the perimeter of the area on the map with a movable tracer point, and the device then automatically calculates and displays the area.
Information Booster
· Function: An instrument used to measure the area of an irregular shape or figure on a map or drawing.
· Operation: The user traces the boundary of the area with a cursor, and the device calculates the area based on the movement of a measuring wheel.
· Accuracy: Provides a much more accurate measurement of irregular areas compared to methods like counting squares.
· Usage: It is a key tool in cartography, geography, civil engineering, and surveying.
· Types: The most common type is the polar planimeter.
Additional Points
· Animometer: A misspelling of Anemometer, an instrument used to measure wind speed.
· Rotameter: An instrument used to measure the flow rate of fluid or gas in a closed tube.
· Clinometer: An instrument used for measuring the angles of slope or elevation.