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Finding the Fourth Proportional to 1,242.72, 1,715 and 690.72

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Solution

The fourth proportional to 1,242.72, 1,715 and 690.72 is: 953.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,242.72 : 1,715 = 690.72 : x
  2. Step 2: Convert to fraction form
    1,242.72/1,715 = 690.72/x
  3. Step 3: Cross multiply
    1,242.72x = 1,715 × 690.72
  4. Step 4: Simplify right side
    1,242.72x = 1,184,584.80
  5. Step 5: Solve for x
    x = 1,184,584.80/1,242.72
  6. Step 6: Final answer
    x = 953.22

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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.