A triangular plot has base 400 m and the perpendicular height to that base is 250 m. Find its area in hectares. (1 hectare = $10000{\text{m}}^2.$)

**Area of a triangle = ½ × base × height.**

The base is any side you choose; the height is the perpendicular distance from that base to the opposite vertex (NOT the slant length of another side). For a right triangle, the two legs that meet at the right angle ARE the base and height.

Example: triangle with base 6 cm and height 4 cm. Area = ½ × $6\times 4=12{\text{cm}}^2$.

The perimeter of a triangle is just the sum of its three sides — no formula needed.