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Finding the Fourth Proportional to 691.60, 955.20 and 515.20

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Solution

The fourth proportional to 691.60, 955.20 and 515.20 is: 711.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    691.60 : 955.20 = 515.20 : x
  2. Step 2: Convert to fraction form
    691.60/955.20 = 515.20/x
  3. Step 3: Cross multiply
    691.60x = 955.20 × 515.20
  4. Step 4: Simplify right side
    691.60x = 492,119.04
  5. Step 5: Solve for x
    x = 492,119.04/691.60
  6. Step 6: Final answer
    x = 711.57

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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.