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Finding the Fourth Proportional to 1,539.70, 2,309.35 and 429.20

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Solution

The fourth proportional to 1,539.70, 2,309.35 and 429.20 is: 643.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,539.70 : 2,309.35 = 429.20 : x
  2. Step 2: Convert to fraction form
    1,539.70/2,309.35 = 429.20/x
  3. Step 3: Cross multiply
    1,539.70x = 2,309.35 × 429.20
  4. Step 4: Simplify right side
    1,539.70x = 991,170.67
  5. Step 5: Solve for x
    x = 991,170.67/1,539.70
  6. Step 6: Final answer
    x = 643.74

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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.