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Finding the Fourth Proportional to 913.40, 1,368.93 and 392.78

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Solution

The fourth proportional to 913.40, 1,368.93 and 392.78 is: 588.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    913.40 : 1,368.93 = 392.78 : x
  2. Step 2: Convert to fraction form
    913.40/1,368.93 = 392.78/x
  3. Step 3: Cross multiply
    913.40x = 1,368.93 × 392.78
  4. Step 4: Simplify right side
    913.40x = 537,693.22
  5. Step 5: Solve for x
    x = 537,693.22/913.40
  6. Step 6: Final answer
    x = 588.67

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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.