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Finding the Fourth Proportional to 704.90, 972.81 and 390.20

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Solution

The fourth proportional to 704.90, 972.81 and 390.20 is: 538.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    704.90 : 972.81 = 390.20 : x
  2. Step 2: Convert to fraction form
    704.90/972.81 = 390.20/x
  3. Step 3: Cross multiply
    704.90x = 972.81 × 390.20
  4. Step 4: Simplify right side
    704.90x = 379,585.60
  5. Step 5: Solve for x
    x = 379,585.60/704.90
  6. Step 6: Final answer
    x = 538.49

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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.