Question 570878
 if you have an isosceles triangle with the legs being 9 and the base is 10 find the altitude.
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Draw the picture:
Draw a perpendicular bisector to the base: (that is the height)
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You have two right triangles with base = 5 ; height = "h" ; 
and hypotenuse = 9
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Pythagoras:
9^2 = 5^2 + h^2
h^2 = 81-25 = 56
h = sqrt(56) (that is the altitude of the isosceles triangle)
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Cheers,
Stan H.