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Finding the Fourth Proportional to 715.95, 988.10 and 421.31

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Solution

The fourth proportional to 715.95, 988.10 and 421.31 is: 581.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    715.95 : 988.10 = 421.31 : x
  2. Step 2: Convert to fraction form
    715.95/988.10 = 421.31/x
  3. Step 3: Cross multiply
    715.95x = 988.10 × 421.31
  4. Step 4: Simplify right side
    715.95x = 416,296.41
  5. Step 5: Solve for x
    x = 416,296.41/715.95
  6. Step 6: Final answer
    x = 581.46

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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.