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Finding the Fourth Proportional to 647.50, 969.78 and 386.99

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Solution

The fourth proportional to 647.50, 969.78 and 386.99 is: 579.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    647.50 : 969.78 = 386.99 : x
  2. Step 2: Convert to fraction form
    647.50/969.78 = 386.99/x
  3. Step 3: Cross multiply
    647.50x = 969.78 × 386.99
  4. Step 4: Simplify right side
    647.50x = 375,290.31
  5. Step 5: Solve for x
    x = 375,290.31/647.50
  6. Step 6: Final answer
    x = 579.60

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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.