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Finding the Fourth Proportional to 565.43, 780 and 390.47

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Solution

The fourth proportional to 565.43, 780 and 390.47 is: 538.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    565.43 : 780 = 390.47 : x
  2. Step 2: Convert to fraction form
    565.43/780 = 390.47/x
  3. Step 3: Cross multiply
    565.43x = 780 × 390.47
  4. Step 4: Simplify right side
    565.43x = 304,562.70
  5. Step 5: Solve for x
    x = 304,562.70/565.43
  6. Step 6: Final answer
    x = 538.64

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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.