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Finding the Fourth Proportional to 928.79, 1,281.75 and 509.15

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Solution

The fourth proportional to 928.79, 1,281.75 and 509.15 is: 702.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    928.79 : 1,281.75 = 509.15 : x
  2. Step 2: Convert to fraction form
    928.79/1,281.75 = 509.15/x
  3. Step 3: Cross multiply
    928.79x = 1,281.75 × 509.15
  4. Step 4: Simplify right side
    928.79x = 652,603.01
  5. Step 5: Solve for x
    x = 652,603.01/928.79
  6. Step 6: Final answer
    x = 702.64

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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.