======Using Mathematics to Estimate a Quantity of Interest such as "How Big is the Sun?"======

Students drew ray diagrams and used prior knowledge of geometry of similar triangles to calculate the diameter of the sun: 

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Variables Used: 
  * H= diameter of the sun
  * h= diameter of the image of the sun
  * D= distance from the sun to the pinhole
  * d= distance from the pinhole to the image

Geometry of similar triangles: ratios of height to distance to pinhole are equal
  * H/D=h/d
  * H= (D)(h)/(d)
  * (100,000,000 miles)(1 cm)/(100cm)= about 1,000,000 miles