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Finding the Fourth Proportional to 670.14, 924.70 and 390.40

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Solution

The fourth proportional to 670.14, 924.70 and 390.40 is: 538.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    670.14 : 924.70 = 390.40 : x
  2. Step 2: Convert to fraction form
    670.14/924.70 = 390.40/x
  3. Step 3: Cross multiply
    670.14x = 924.70 × 390.40
  4. Step 4: Simplify right side
    670.14x = 361,002.88
  5. Step 5: Solve for x
    x = 361,002.88/670.14
  6. Step 6: Final answer
    x = 538.70

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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.