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Finding the Fourth Proportional to 718.92, 1,078.40 and 307.80

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Solution

The fourth proportional to 718.92, 1,078.40 and 307.80 is: 461.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    718.92 : 1,078.40 = 307.80 : x
  2. Step 2: Convert to fraction form
    718.92/1,078.40 = 307.80/x
  3. Step 3: Cross multiply
    718.92x = 1,078.40 × 307.80
  4. Step 4: Simplify right side
    718.92x = 331,931.52
  5. Step 5: Solve for x
    x = 331,931.52/718.92
  6. Step 6: Final answer
    x = 461.71

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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.