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Finding the Fourth Proportional to 786.60, 1,085.40 and 487.85

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Solution

The fourth proportional to 786.60, 1,085.40 and 487.85 is: 673.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    786.60 : 1,085.40 = 487.85 : x
  2. Step 2: Convert to fraction form
    786.60/1,085.40 = 487.85/x
  3. Step 3: Cross multiply
    786.60x = 1,085.40 × 487.85
  4. Step 4: Simplify right side
    786.60x = 529,506.96
  5. Step 5: Solve for x
    x = 529,506.96/786.60
  6. Step 6: Final answer
    x = 673.16

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.