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Finding the Fourth Proportional to 684.95, 945.18 and 390.20

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Solution

The fourth proportional to 684.95, 945.18 and 390.20 is: 538.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    684.95 : 945.18 = 390.20 : x
  2. Step 2: Convert to fraction form
    684.95/945.18 = 390.20/x
  3. Step 3: Cross multiply
    684.95x = 945.18 × 390.20
  4. Step 4: Simplify right side
    684.95x = 368,804.51
  5. Step 5: Solve for x
    x = 368,804.51/684.95
  6. Step 6: Final answer
    x = 538.44

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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.