Question 180767
an apartment building casts a shadow. From the tip of the shadow to the top of the building is 100 m. The tip of the shadow is 72 m from the base of the building? How tall is the building? 
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Draw the picture and label the height of the building "x".
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Use Pythagoras or use trigonometry if you know it.

100^2 = 72^2 + x^2
x^2 = 10000 - 5184
x^2 = 4816
x = 69.40 meters

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Cheers,
Stan H.