Topic explanation

Standard explanation

Need two sides and the included angle. If the angle is not included, find it first or use Heron after all sides.

Key points

• included angle
• (12)ab sin C
• Heron uses S
• keep the ideas separate
• Sas Area: Need two sides and the included angle. If the angle is not included, find it first or use Heron afte
• WHAT — SAS AREA: Need two sides and the included angle. If the angle is not included, find it first or use Heron afte
• HOW — Use the idea: Identify what is given, select this topic's rule or evidence, apply it one step at a time, and check
• CORE UNDERSTANDING: Need two sides and the included angle. If the angle is not included, find it first or use Heron afte

Labelled diagram