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Finding the Fourth Proportional to 520.50, 780.75 and 135.75

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Solution

The fourth proportional to 520.50, 780.75 and 135.75 is: 203.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    520.50 : 780.75 = 135.75 : x
  2. Step 2: Convert to fraction form
    520.50/780.75 = 135.75/x
  3. Step 3: Cross multiply
    520.50x = 780.75 × 135.75
  4. Step 4: Simplify right side
    520.50x = 105,986.81
  5. Step 5: Solve for x
    x = 105,986.81/520.50
  6. Step 6: Final answer
    x = 203.63

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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.