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Finding the Fourth Proportional to 509.40, 702.78 and 312.84

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Solution

The fourth proportional to 509.40, 702.78 and 312.84 is: 431.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    509.40 : 702.78 = 312.84 : x
  2. Step 2: Convert to fraction form
    509.40/702.78 = 312.84/x
  3. Step 3: Cross multiply
    509.40x = 702.78 × 312.84
  4. Step 4: Simplify right side
    509.40x = 219,857.70
  5. Step 5: Solve for x
    x = 219,857.70/509.40
  6. Step 6: Final answer
    x = 431.60

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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.