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Finding the Fourth Proportional to 691.30, 1,036.95 and 258.50

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Solution

The fourth proportional to 691.30, 1,036.95 and 258.50 is: 387.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    691.30 : 1,036.95 = 258.50 : x
  2. Step 2: Convert to fraction form
    691.30/1,036.95 = 258.50/x
  3. Step 3: Cross multiply
    691.30x = 1,036.95 × 258.50
  4. Step 4: Simplify right side
    691.30x = 268,051.58
  5. Step 5: Solve for x
    x = 268,051.58/691.30
  6. Step 6: Final answer
    x = 387.75

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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.