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Finding the Fourth Proportional to 520, 780 and 154.78

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Solution

The fourth proportional to 520, 780 and 154.78 is: 232.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    520 : 780 = 154.78 : x
  2. Step 2: Convert to fraction form
    520/780 = 154.78/x
  3. Step 3: Cross multiply
    520x = 780 × 154.78
  4. Step 4: Simplify right side
    520x = 120,728.40
  5. Step 5: Solve for x
    x = 120,728.40/520
  6. Step 6: Final answer
    x = 232.17

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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.