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Finding the Fourth Proportional to 691.14, 1,036.71 and 386.50

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Solution

The fourth proportional to 691.14, 1,036.71 and 386.50 is: 579.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    691.14 : 1,036.71 = 386.50 : x
  2. Step 2: Convert to fraction form
    691.14/1,036.71 = 386.50/x
  3. Step 3: Cross multiply
    691.14x = 1,036.71 × 386.50
  4. Step 4: Simplify right side
    691.14x = 400,688.42
  5. Step 5: Solve for x
    x = 400,688.42/691.14
  6. Step 6: Final answer
    x = 579.75

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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.