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Finding the Fourth Proportional to 478.68, 661.50 and 389.98

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Solution

The fourth proportional to 478.68, 661.50 and 389.98 is: 538.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    478.68 : 661.50 = 389.98 : x
  2. Step 2: Convert to fraction form
    478.68/661.50 = 389.98/x
  3. Step 3: Cross multiply
    478.68x = 661.50 × 389.98
  4. Step 4: Simplify right side
    478.68x = 257,971.77
  5. Step 5: Solve for x
    x = 257,971.77/478.68
  6. Step 6: Final answer
    x = 538.92

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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.