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Finding the Fourth Proportional to 515.51, 712.10 and 491.21

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Solution

The fourth proportional to 515.51, 712.10 and 491.21 is: 678.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    515.51 : 712.10 = 491.21 : x
  2. Step 2: Convert to fraction form
    515.51/712.10 = 491.21/x
  3. Step 3: Cross multiply
    515.51x = 712.10 × 491.21
  4. Step 4: Simplify right side
    515.51x = 349,788.18
  5. Step 5: Solve for x
    x = 349,788.18/515.51
  6. Step 6: Final answer
    x = 678.53

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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.