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Finding the Fourth Proportional to 670.50, 925.20 and 390.60

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Solution

The fourth proportional to 670.50, 925.20 and 390.60 is: 538.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    670.50 : 925.20 = 390.60 : x
  2. Step 2: Convert to fraction form
    670.50/925.20 = 390.60/x
  3. Step 3: Cross multiply
    670.50x = 925.20 × 390.60
  4. Step 4: Simplify right side
    670.50x = 361,383.12
  5. Step 5: Solve for x
    x = 361,383.12/670.50
  6. Step 6: Final answer
    x = 538.98

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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.