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Finding the Fourth Proportional to 978.30, 1,349.32 and 623.86

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Solution

The fourth proportional to 978.30, 1,349.32 and 623.86 is: 860.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.30 : 1,349.32 = 623.86 : x
  2. Step 2: Convert to fraction form
    978.30/1,349.32 = 623.86/x
  3. Step 3: Cross multiply
    978.30x = 1,349.32 × 623.86
  4. Step 4: Simplify right side
    978.30x = 841,786.78
  5. Step 5: Solve for x
    x = 841,786.78/978.30
  6. Step 6: Final answer
    x = 860.46

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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.