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Finding the Fourth Proportional to 500.61, 690.53 and 390.05

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Solution

The fourth proportional to 500.61, 690.53 and 390.05 is: 538.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    500.61 : 690.53 = 390.05 : x
  2. Step 2: Convert to fraction form
    500.61/690.53 = 390.05/x
  3. Step 3: Cross multiply
    500.61x = 690.53 × 390.05
  4. Step 4: Simplify right side
    500.61x = 269,338.41
  5. Step 5: Solve for x
    x = 269,338.41/500.61
  6. Step 6: Final answer
    x = 538.02

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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.