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Finding the Fourth Proportional to 670.45, 1,005.72 and 426.64

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Solution

The fourth proportional to 670.45, 1,005.72 and 426.64 is: 639.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    670.45 : 1,005.72 = 426.64 : x
  2. Step 2: Convert to fraction form
    670.45/1,005.72 = 426.64/x
  3. Step 3: Cross multiply
    670.45x = 1,005.72 × 426.64
  4. Step 4: Simplify right side
    670.45x = 429,080.38
  5. Step 5: Solve for x
    x = 429,080.38/670.45
  6. Step 6: Final answer
    x = 639.99

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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.