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Finding the Fourth Proportional to 909.64, 1,253.50 and 647.20

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Solution

The fourth proportional to 909.64, 1,253.50 and 647.20 is: 891.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    909.64 : 1,253.50 = 647.20 : x
  2. Step 2: Convert to fraction form
    909.64/1,253.50 = 647.20/x
  3. Step 3: Cross multiply
    909.64x = 1,253.50 × 647.20
  4. Step 4: Simplify right side
    909.64x = 811,265.20
  5. Step 5: Solve for x
    x = 811,265.20/909.64
  6. Step 6: Final answer
    x = 891.85

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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.