If a parallelogram and a triangle stand on the same base and between the same parallel lines, the area of the triangle is ____ the area of the parallelogram.

**Area of a parallelogram = base × height.**

Same idea as a rectangle, but the height is the perpendicular distance between the two parallel sides — NOT the slant length of the side. Pick any side as the base, drop a perpendicular to the opposite parallel side, measure that — that's the height.

Example: parallelogram with base 8 cm and perpendicular height 5 cm. Area = $8\times 5=40{\text{cm}}^2$. The slant side could be longer; doesn't matter for area.

Perimeter of a parallelogram = 2 × (one side + adjacent side).