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Finding the Fourth Proportional to 691.76, 1,038.16 and 258.96

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Solution

The fourth proportional to 691.76, 1,038.16 and 258.96 is: 388.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    691.76 : 1,038.16 = 258.96 : x
  2. Step 2: Convert to fraction form
    691.76/1,038.16 = 258.96/x
  3. Step 3: Cross multiply
    691.76x = 1,038.16 × 258.96
  4. Step 4: Simplify right side
    691.76x = 268,841.91
  5. Step 5: Solve for x
    x = 268,841.91/691.76
  6. Step 6: Final answer
    x = 388.63

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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.