Question

Q.2.B) Solve the following questions( 2 mark each)
1. If(a + b + c)(a -b + c) = a²+ b² + c² hen show that a,b,c are in
continued proportion.​

Answer 1

if elements are in gp then those elements are in continuous proportion

Answer 2

Solution :

(a + b + c)( a - b + c ) = a² + b² + c²

→ a ( a - b + c ) + b ( a - b + c ) + c ( a - b + c ) = a² + b² + c² .

→ a² - ab + ac + ab - b² + bc + ca - bc + c² = a² + b² + c²

→ a² - b² + c² + 2ac = a² + b² + c²

→ 2b² = 2ac

→ b² = ac

→ b × b = a × c

→ b / a = c / b .

→ a : b :: b : c .

Hence , a , b , and c are in continued proportion .

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