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Finding the Fourth Proportional to 690.42, 1,035.21 and 430.83

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Solution

The fourth proportional to 690.42, 1,035.21 and 430.83 is: 645.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.42 : 1,035.21 = 430.83 : x
  2. Step 2: Convert to fraction form
    690.42/1,035.21 = 430.83/x
  3. Step 3: Cross multiply
    690.42x = 1,035.21 × 430.83
  4. Step 4: Simplify right side
    690.42x = 445,999.52
  5. Step 5: Solve for x
    x = 445,999.52/690.42
  6. Step 6: Final answer
    x = 645.98

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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.