Mathematics · Grades 5–9
Geometry: justify, do not just measure · Revision card
A drawing may not be to scale. Apply the stated properties.
Understand the idea
Use defining properties
A drawing may not be to scale. Apply the stated properties.
Separate measures
Perimeter measures boundary length; area measures surface coverage.
State assumptions
Angle rules here use ordinary plane Euclidean geometry.
Worked examples
Two angles in a triangle are 48° and 67°. Find the third angle in degrees.
180 − 48 − 67 = 65.
65
Which statement is true for every square?
These properties define a square in plane geometry.
It has four equal sides and four right angles.
Explain without looking
- A triangle of base 14 cm has area 42 cm². Find its perpendicular height in cm.
Preview material · independent educational review required. Grade bands are approximate, not official curriculum alignment.