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Finding the Fourth Proportional to 684.85, 945.09 and 390.11

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Solution

The fourth proportional to 684.85, 945.09 and 390.11 is: 538.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    684.85 : 945.09 = 390.11 : x
  2. Step 2: Convert to fraction form
    684.85/945.09 = 390.11/x
  3. Step 3: Cross multiply
    684.85x = 945.09 × 390.11
  4. Step 4: Simplify right side
    684.85x = 368,689.06
  5. Step 5: Solve for x
    x = 368,689.06/684.85
  6. Step 6: Final answer
    x = 538.35

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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.