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Finding the Fourth Proportional to 501.51, 691.60 and 390.95

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Solution

The fourth proportional to 501.51, 691.60 and 390.95 is: 539.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    501.51 : 691.60 = 390.95 : x
  2. Step 2: Convert to fraction form
    501.51/691.60 = 390.95/x
  3. Step 3: Cross multiply
    501.51x = 691.60 × 390.95
  4. Step 4: Simplify right side
    501.51x = 270,381.02
  5. Step 5: Solve for x
    x = 270,381.02/501.51
  6. Step 6: Final answer
    x = 539.13

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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.