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Finding the Fourth Proportional to 921.40, 1,271.51 and 528.40

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Solution

The fourth proportional to 921.40, 1,271.51 and 528.40 is: 729.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    921.40 : 1,271.51 = 528.40 : x
  2. Step 2: Convert to fraction form
    921.40/1,271.51 = 528.40/x
  3. Step 3: Cross multiply
    921.40x = 1,271.51 × 528.40
  4. Step 4: Simplify right side
    921.40x = 671,863.98
  5. Step 5: Solve for x
    x = 671,863.98/921.40
  6. Step 6: Final answer
    x = 729.18

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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.