Grade 8 - Measurement

Students determine radius and diameter using $d=2r$ and $r=d/2$, and calculate circle circumference with $C=2\pi r=\pi d$ and area with $A=\pi r^2$, reporting linear or square units and exact or appropriately approximated values. They find the area of polygonal composite figures by decomposing or subtracting familiar regions and convert metric units of length, area, and volume across millimeters, centimeters, meters, and kilometers using factors of $10$, $10^2$, and $10^3$, respectively. They calculate prism and cylinder volumes and surface areas using $V=Bh$, $V=\pi r^2h$, $SA=2B+Ph$, and $SA=2\pi r^2+2\pi rh$, and solve composite-solid problems by adding component measures or subtracting missing sections while excluding shared internal surfaces from exterior area.