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Finding the Fourth Proportional to 1,186.72, 1,637.76 and 689.40

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Solution

The fourth proportional to 1,186.72, 1,637.76 and 689.40 is: 951.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,186.72 : 1,637.76 = 689.40 : x
  2. Step 2: Convert to fraction form
    1,186.72/1,637.76 = 689.40/x
  3. Step 3: Cross multiply
    1,186.72x = 1,637.76 × 689.40
  4. Step 4: Simplify right side
    1,186.72x = 1,129,071.74
  5. Step 5: Solve for x
    x = 1,129,071.74/1,186.72
  6. Step 6: Final answer
    x = 951.42

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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.