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Finding the Fourth Proportional to 645.12, 889.20 and 497.70

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Solution

The fourth proportional to 645.12, 889.20 and 497.70 is: 686.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.12 : 889.20 = 497.70 : x
  2. Step 2: Convert to fraction form
    645.12/889.20 = 497.70/x
  3. Step 3: Cross multiply
    645.12x = 889.20 × 497.70
  4. Step 4: Simplify right side
    645.12x = 442,554.84
  5. Step 5: Solve for x
    x = 442,554.84/645.12
  6. Step 6: Final answer
    x = 686.00

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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.