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Finding the Fourth Proportional to 699.17, 1,048.77 and 390.78

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Solution

The fourth proportional to 699.17, 1,048.77 and 390.78 is: 586.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    699.17 : 1,048.77 = 390.78 : x
  2. Step 2: Convert to fraction form
    699.17/1,048.77 = 390.78/x
  3. Step 3: Cross multiply
    699.17x = 1,048.77 × 390.78
  4. Step 4: Simplify right side
    699.17x = 409,838.34
  5. Step 5: Solve for x
    x = 409,838.34/699.17
  6. Step 6: Final answer
    x = 586.18

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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.