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Finding the Fourth Proportional to 929.60, 1,390.35 and 783.80

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Solution

The fourth proportional to 929.60, 1,390.35 and 783.80 is: 1,172.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    929.60 : 1,390.35 = 783.80 : x
  2. Step 2: Convert to fraction form
    929.60/1,390.35 = 783.80/x
  3. Step 3: Cross multiply
    929.60x = 1,390.35 × 783.80
  4. Step 4: Simplify right side
    929.60x = 1,089,756.33
  5. Step 5: Solve for x
    x = 1,089,756.33/929.60
  6. Step 6: Final answer
    x = 1,172.29

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.