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Finding the Fourth Proportional to 978.76, 1,465.10 and 521.80

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Solution

The fourth proportional to 978.76, 1,465.10 and 521.80 is: 781.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.76 : 1,465.10 = 521.80 : x
  2. Step 2: Convert to fraction form
    978.76/1,465.10 = 521.80/x
  3. Step 3: Cross multiply
    978.76x = 1,465.10 × 521.80
  4. Step 4: Simplify right side
    978.76x = 764,489.18
  5. Step 5: Solve for x
    x = 764,489.18/978.76
  6. Step 6: Final answer
    x = 781.08

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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.