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Finding the Fourth Proportional to 670.39, 1,005.68 and 208.20

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Solution

The fourth proportional to 670.39, 1,005.68 and 208.20 is: 312.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    670.39 : 1,005.68 = 208.20 : x
  2. Step 2: Convert to fraction form
    670.39/1,005.68 = 208.20/x
  3. Step 3: Cross multiply
    670.39x = 1,005.68 × 208.20
  4. Step 4: Simplify right side
    670.39x = 209,386.87
  5. Step 5: Solve for x
    x = 209,386.87/670.39
  6. Step 6: Final answer
    x = 312.34

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.