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In isosceles triangle ABC, D is a point ...

In isosceles triangle ABC, D is a point on the base BC produced. Prove that `AD gt AB`.

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In `Delta ABC`
`AB=AC`
`implies" "angleACB=angleABC` ...(1)
In `DeltaACD`
`angle ACB=angle ADC+angleCAD" "( :' angle ACB" is exterior angle")`
`implies" "angleACB gt angleADC`
`implies" "angleABC gt angle ADC` [from (I)]
`implies" "angleABD gt angle ADB`
`implies" "AD gt AB` Hence Proved.
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