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Finding the Fourth Proportional to 390.94, 586.40 and 102.40

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Solution

The fourth proportional to 390.94, 586.40 and 102.40 is: 153.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.94 : 586.40 = 102.40 : x
  2. Step 2: Convert to fraction form
    390.94/586.40 = 102.40/x
  3. Step 3: Cross multiply
    390.94x = 586.40 × 102.40
  4. Step 4: Simplify right side
    390.94x = 60,047.36
  5. Step 5: Solve for x
    x = 60,047.36/390.94
  6. Step 6: Final answer
    x = 153.60

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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.