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Finding the Fourth Proportional to 420.24, 579.96 and 386.76

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Solution

The fourth proportional to 420.24, 579.96 and 386.76 is: 533.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.24 : 579.96 = 386.76 : x
  2. Step 2: Convert to fraction form
    420.24/579.96 = 386.76/x
  3. Step 3: Cross multiply
    420.24x = 579.96 × 386.76
  4. Step 4: Simplify right side
    420.24x = 224,305.33
  5. Step 5: Solve for x
    x = 224,305.33/420.24
  6. Step 6: Final answer
    x = 533.76

Related Problems

Find fourth proportional to 210.12, 289.98 and 193.38
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Double scale
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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.