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Finding the Fourth Proportional to 565.76, 780.36 and 390.80

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Solution

The fourth proportional to 565.76, 780.36 and 390.80 is: 539.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    565.76 : 780.36 = 390.80 : x
  2. Step 2: Convert to fraction form
    565.76/780.36 = 390.80/x
  3. Step 3: Cross multiply
    565.76x = 780.36 × 390.80
  4. Step 4: Simplify right side
    565.76x = 304,964.69
  5. Step 5: Solve for x
    x = 304,964.69/565.76
  6. Step 6: Final answer
    x = 539.04

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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.