Home / 371.78-557.72-128.31

Finding the Fourth Proportional to 371.78, 557.72 and 128.31

Calculator

Solution

The fourth proportional to 371.78, 557.72 and 128.31 is: 192.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    371.78 : 557.72 = 128.31 : x
  2. Step 2: Convert to fraction form
    371.78/557.72 = 128.31/x
  3. Step 3: Cross multiply
    371.78x = 557.72 × 128.31
  4. Step 4: Simplify right side
    371.78x = 71,560.41
  5. Step 5: Solve for x
    x = 71,560.41/371.78
  6. Step 6: Final answer
    x = 192.48

Related Problems

Find fourth proportional to 185.89, 278.86 and 64.16
Half scale
Find fourth proportional to 743.55, 1,115.43 and 256.62
Double scale
Find fourth proportional to 372.78, 559.22 and 129.31
Similar ratio
Find fourth proportional to 557.66, 836.57 and 192.47
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.