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Finding the Fourth Proportional to 515.15, 710.90 and 279.10

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Solution

The fourth proportional to 515.15, 710.90 and 279.10 is: 385.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    515.15 : 710.90 = 279.10 : x
  2. Step 2: Convert to fraction form
    515.15/710.90 = 279.10/x
  3. Step 3: Cross multiply
    515.15x = 710.90 × 279.10
  4. Step 4: Simplify right side
    515.15x = 198,408.64
  5. Step 5: Solve for x
    x = 198,408.64/515.15
  6. Step 6: Final answer
    x = 385.15

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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.