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Finding the Fourth Proportional to 809.76, 1,117.29 and 515.40

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Solution

The fourth proportional to 809.76, 1,117.29 and 515.40 is: 711.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.76 : 1,117.29 = 515.40 : x
  2. Step 2: Convert to fraction form
    809.76/1,117.29 = 515.40/x
  3. Step 3: Cross multiply
    809.76x = 1,117.29 × 515.40
  4. Step 4: Simplify right side
    809.76x = 575,851.27
  5. Step 5: Solve for x
    x = 575,851.27/809.76
  6. Step 6: Final answer
    x = 711.14

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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.