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Finding the Fourth Proportional to 715.94, 987.86 and 421.13

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Solution

The fourth proportional to 715.94, 987.86 and 421.13 is: 581.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    715.94 : 987.86 = 421.13 : x
  2. Step 2: Convert to fraction form
    715.94/987.86 = 421.13/x
  3. Step 3: Cross multiply
    715.94x = 987.86 × 421.13
  4. Step 4: Simplify right side
    715.94x = 416,021.00
  5. Step 5: Solve for x
    x = 416,021.00/715.94
  6. Step 6: Final answer
    x = 581.08

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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.