Math 1 · Unit 11 · Lesson 3 · part 1 of 5

The Words We Use

The vocabulary for this lesson, in one place.

Words we use

WordPlain EnglishWhat you do
PerimeterThe distance all the way around a shape.Distance for every side, then add.
AreaHow much flat space a shape covers, in square units.Rectangle: length times width. Triangle: one half base times height.
Base and heightFor a triangle, a side and the perpendicular distance to the opposite corner.Check perpendicular with slopes first.
AltitudeA segment from a corner that meets the opposite side at a right angle: the height.Its slope is the negative reciprocal of the base's slope.
Vertex (vertices)A corner of a shape.Name the shape by its vertices in order.
Box methodDraw a rectangle around the shape on the grid lines, then subtract the corner pieces.For shapes with no easy height.

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