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Finding the Fourth Proportional to 978.19, 1,462.90 and 869.18

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Solution

The fourth proportional to 978.19, 1,462.90 and 869.18 is: 1,299.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.19 : 1,462.90 = 869.18 : x
  2. Step 2: Convert to fraction form
    978.19/1,462.90 = 869.18/x
  3. Step 3: Cross multiply
    978.19x = 1,462.90 × 869.18
  4. Step 4: Simplify right side
    978.19x = 1,271,523.42
  5. Step 5: Solve for x
    x = 1,271,523.42/978.19
  6. Step 6: Final answer
    x = 1,299.87

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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.