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Finding the Fourth Proportional to 669.78, 924.39 and 390.15

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Solution

The fourth proportional to 669.78, 924.39 and 390.15 is: 538.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    669.78 : 924.39 = 390.15 : x
  2. Step 2: Convert to fraction form
    669.78/924.39 = 390.15/x
  3. Step 3: Cross multiply
    669.78x = 924.39 × 390.15
  4. Step 4: Simplify right side
    669.78x = 360,650.76
  5. Step 5: Solve for x
    x = 360,650.76/669.78
  6. Step 6: Final answer
    x = 538.46

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1.5x scale

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.