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Finding the Fourth Proportional to 655.79, 904.89 and 390.15

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Solution

The fourth proportional to 655.79, 904.89 and 390.15 is: 538.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    655.79 : 904.89 = 390.15 : x
  2. Step 2: Convert to fraction form
    655.79/904.89 = 390.15/x
  3. Step 3: Cross multiply
    655.79x = 904.89 × 390.15
  4. Step 4: Simplify right side
    655.79x = 353,042.83
  5. Step 5: Solve for x
    x = 353,042.83/655.79
  6. Step 6: Final answer
    x = 538.35

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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.