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Finding the Fourth Proportional to 715.14, 987.72 and 478.74

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Solution

The fourth proportional to 715.14, 987.72 and 478.74 is: 661.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    715.14 : 987.72 = 478.74 : x
  2. Step 2: Convert to fraction form
    715.14/987.72 = 478.74/x
  3. Step 3: Cross multiply
    715.14x = 987.72 × 478.74
  4. Step 4: Simplify right side
    715.14x = 472,861.07
  5. Step 5: Solve for x
    x = 472,861.07/715.14
  6. Step 6: Final answer
    x = 661.21

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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.