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Finding the Fourth Proportional to 1,298.76, 1,947.64 and 420.96

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Solution

The fourth proportional to 1,298.76, 1,947.64 and 420.96 is: 631.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,298.76 : 1,947.64 = 420.96 : x
  2. Step 2: Convert to fraction form
    1,298.76/1,947.64 = 420.96/x
  3. Step 3: Cross multiply
    1,298.76x = 1,947.64 × 420.96
  4. Step 4: Simplify right side
    1,298.76x = 819,878.53
  5. Step 5: Solve for x
    x = 819,878.53/1,298.76
  6. Step 6: Final answer
    x = 631.28

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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.