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Finding the Fourth Proportional to 710, 979.80 and 399.50

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Solution

The fourth proportional to 710, 979.80 and 399.50 is: 551.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    710 : 979.80 = 399.50 : x
  2. Step 2: Convert to fraction form
    710/979.80 = 399.50/x
  3. Step 3: Cross multiply
    710x = 979.80 × 399.50
  4. Step 4: Simplify right side
    710x = 391,430.10
  5. Step 5: Solve for x
    x = 391,430.10/710
  6. Step 6: Final answer
    x = 551.31

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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.