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Finding the Fourth Proportional to 1,128.42, 1,688.37 and 666.45

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Solution

The fourth proportional to 1,128.42, 1,688.37 and 666.45 is: 997.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,128.42 : 1,688.37 = 666.45 : x
  2. Step 2: Convert to fraction form
    1,128.42/1,688.37 = 666.45/x
  3. Step 3: Cross multiply
    1,128.42x = 1,688.37 × 666.45
  4. Step 4: Simplify right side
    1,128.42x = 1,125,214.19
  5. Step 5: Solve for x
    x = 1,125,214.19/1,128.42
  6. Step 6: Final answer
    x = 997.16

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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.