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Finding the Fourth Proportional to 510.90, 705 and 289.80

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Solution

The fourth proportional to 510.90, 705 and 289.80 is: 399.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    510.90 : 705 = 289.80 : x
  2. Step 2: Convert to fraction form
    510.90/705 = 289.80/x
  3. Step 3: Cross multiply
    510.90x = 705 × 289.80
  4. Step 4: Simplify right side
    510.90x = 204,309
  5. Step 5: Solve for x
    x = 204,309/510.90
  6. Step 6: Final answer
    x = 399.90

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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.