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Finding the Fourth Proportional to 913.60, 1,370.58 and 639.76

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Solution

The fourth proportional to 913.60, 1,370.58 and 639.76 is: 959.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    913.60 : 1,370.58 = 639.76 : x
  2. Step 2: Convert to fraction form
    913.60/1,370.58 = 639.76/x
  3. Step 3: Cross multiply
    913.60x = 1,370.58 × 639.76
  4. Step 4: Simplify right side
    913.60x = 876,842.26
  5. Step 5: Solve for x
    x = 876,842.26/913.60
  6. Step 6: Final answer
    x = 959.77

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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.