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Finding the Fourth Proportional to 864.90, 1,298.88 and 645.66

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Solution

The fourth proportional to 864.90, 1,298.88 and 645.66 is: 969.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    864.90 : 1,298.88 = 645.66 : x
  2. Step 2: Convert to fraction form
    864.90/1,298.88 = 645.66/x
  3. Step 3: Cross multiply
    864.90x = 1,298.88 × 645.66
  4. Step 4: Simplify right side
    864.90x = 838,634.86
  5. Step 5: Solve for x
    x = 838,634.86/864.90
  6. Step 6: Final answer
    x = 969.63

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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.