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Finding the Fourth Proportional to 661.18, 912.40 and 381.40

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Solution

The fourth proportional to 661.18, 912.40 and 381.40 is: 526.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.18 : 912.40 = 381.40 : x
  2. Step 2: Convert to fraction form
    661.18/912.40 = 381.40/x
  3. Step 3: Cross multiply
    661.18x = 912.40 × 381.40
  4. Step 4: Simplify right side
    661.18x = 347,989.36
  5. Step 5: Solve for x
    x = 347,989.36/661.18
  6. Step 6: Final answer
    x = 526.32

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Double scale
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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.