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Finding the Fourth Proportional to 928.50, 1,281.86 and 645.32

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Solution

The fourth proportional to 928.50, 1,281.86 and 645.32 is: 890.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    928.50 : 1,281.86 = 645.32 : x
  2. Step 2: Convert to fraction form
    928.50/1,281.86 = 645.32/x
  3. Step 3: Cross multiply
    928.50x = 1,281.86 × 645.32
  4. Step 4: Simplify right side
    928.50x = 827,209.90
  5. Step 5: Solve for x
    x = 827,209.90/928.50
  6. Step 6: Final answer
    x = 890.91

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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.