Home / 256.47-384.39-215.79

Finding the Fourth Proportional to 256.47, 384.39 and 215.79

Calculator

Solution

The fourth proportional to 256.47, 384.39 and 215.79 is: 323.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    256.47 : 384.39 = 215.79 : x
  2. Step 2: Convert to fraction form
    256.47/384.39 = 215.79/x
  3. Step 3: Cross multiply
    256.47x = 384.39 × 215.79
  4. Step 4: Simplify right side
    256.47x = 82,947.52
  5. Step 5: Solve for x
    x = 82,947.52/256.47
  6. Step 6: Final answer
    x = 323.42

Related Problems

Find fourth proportional to 128.24, 192.20 and 107.90
Half scale
Find fourth proportional to 512.94, 768.78 and 431.58
Double scale
Find fourth proportional to 257.47, 385.89 and 216.79
Similar ratio
Find fourth proportional to 384.71, 576.59 and 323.69
1.5x scale

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.