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Finding the Fourth Proportional to 691.85, 1,038.53 and 615.31

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Solution

The fourth proportional to 691.85, 1,038.53 and 615.31 is: 923.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    691.85 : 1,038.53 = 615.31 : x
  2. Step 2: Convert to fraction form
    691.85/1,038.53 = 615.31/x
  3. Step 3: Cross multiply
    691.85x = 1,038.53 × 615.31
  4. Step 4: Simplify right side
    691.85x = 639,009.63
  5. Step 5: Solve for x
    x = 639,009.63/691.85
  6. Step 6: Final answer
    x = 923.62

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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.