Triangle area from two sides and the included angle
Mathematics · Grade 10 · about 40 minutes
When the perpendicular height is not given, area is half the product of two sides times the sine of the angle between them.
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Other lessons in this sub-strand
- Areas of triangles and quadrilaterals
- Regular polygons and composite shapes
- Perpendicular height, not the slant
- Triangle area from two sides and the included angle
- Heron's formula: three sides, no height
- Area of a parallelogram from sides and an angle
- Rhombus: base times height, or half the diagonals
- Area of a kite
- Trapezium: finding a missing length
- A regular polygon as n isosceles triangles
- Frames, paths and holes: subtract to add
- Irregular polygons by triangulation
- Square metres, hectares and acres
- Paint, tiles, fertiliser and land cost