Measurement and Data
What this domain covers
Measurement and Data tests converting units within one measurement system, solving area and perimeter problems, interpreting line plots with fractional data, and measuring angles. You need to choose the right unit, formula, or scale and keep track of square versus linear units.
Core rules to know
- Unit conversion: multiply when converting from a larger unit to a smaller unit; divide for the reverse. 1 km = 1,000 m; 1 m = 100 cm; 1 kg = 1,000 g; 1 L = 1,000 mL; 1 hr = 60 min.
- Area and perimeter: area of a rectangle = length × width, in square units. Perimeter = 2(length + width), in linear units. A composite figure can be split into rectangles.
- Line plots: each X represents one data value. Read the scale and count Xs at each fraction or whole number.
- Angles: a right angle is 90°, a straight angle is 180°. Angles can be added when they share a vertex and non-overlapping interiors.
Worked example
A rectangular garden is 12 m long and 5 m wide. Find its area and perimeter. Area = 12 × 5 = 60 square meters. Perimeter = 12 + 5 + 12 + 5 = 34 meters, or 2(12 + 5) = 34 m. Area measures the surface covered; perimeter measures the distance around. The units differ.
Traps that cost marks
- Reporting area in meters instead of square meters.
- Multiplying by 100 when converting meters to centimeters but forgetting to move every digit.
- Reading a line plot scale as 1 when each tick is 1/4.
- Adding lengths of all sides but labeling the result as area.
- Using 100° for a right angle or 360° for a straight angle.