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Finding the Fourth Proportional to 978.80, 1,468.16 and 430.84

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Solution

The fourth proportional to 978.80, 1,468.16 and 430.84 is: 646.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.80 : 1,468.16 = 430.84 : x
  2. Step 2: Convert to fraction form
    978.80/1,468.16 = 430.84/x
  3. Step 3: Cross multiply
    978.80x = 1,468.16 × 430.84
  4. Step 4: Simplify right side
    978.80x = 632,542.05
  5. Step 5: Solve for x
    x = 632,542.05/978.80
  6. Step 6: Final answer
    x = 646.24

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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.