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Finding the Fourth Proportional to 938.19, 1,407.45 and 390.09

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Solution

The fourth proportional to 938.19, 1,407.45 and 390.09 is: 585.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    938.19 : 1,407.45 = 390.09 : x
  2. Step 2: Convert to fraction form
    938.19/1,407.45 = 390.09/x
  3. Step 3: Cross multiply
    938.19x = 1,407.45 × 390.09
  4. Step 4: Simplify right side
    938.19x = 549,032.17
  5. Step 5: Solve for x
    x = 549,032.17/938.19
  6. Step 6: Final answer
    x = 585.20

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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.