How to Pythagorean theorem is a fundamental concept in geometry.
How to use the Pythagorean theorem.
Triangles Solutions for Class 10th Maths, EXERCISE 6.6, Questions No:2
CBSE Board and Others state Board.
ABC is a triangle in which ∠ABC > 90° and AD ⊥ CB produced. Prove that AC²= AB² + BC² + 2 BC . BD.
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In ΔADB, by pythagoras theorem
AB² = AD² + DB² …(1)
In ΔACD, by pythagoras theorem
AC² = AD² + DC²
⇒AC² = AD² + (DB + BC)²
⇒AC² = AD² + BD² + BC² + 2DB BC
⇒AC² = AB² + BC² + 2DB × BC [From the equation (1)]