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Finding the Fourth Proportional to 978.16, 1,347.96 and 729.76

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Solution

The fourth proportional to 978.16, 1,347.96 and 729.76 is: 1,005.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.16 : 1,347.96 = 729.76 : x
  2. Step 2: Convert to fraction form
    978.16/1,347.96 = 729.76/x
  3. Step 3: Cross multiply
    978.16x = 1,347.96 × 729.76
  4. Step 4: Simplify right side
    978.16x = 983,687.29
  5. Step 5: Solve for x
    x = 983,687.29/978.16
  6. Step 6: Final answer
    x = 1,005.65

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.