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Finding the Fourth Proportional to 972.40, 1,457.72 and 387.80

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Solution

The fourth proportional to 972.40, 1,457.72 and 387.80 is: 581.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    972.40 : 1,457.72 = 387.80 : x
  2. Step 2: Convert to fraction form
    972.40/1,457.72 = 387.80/x
  3. Step 3: Cross multiply
    972.40x = 1,457.72 × 387.80
  4. Step 4: Simplify right side
    972.40x = 565,301.88
  5. Step 5: Solve for x
    x = 565,301.88/972.40
  6. Step 6: Final answer
    x = 581.35

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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.