Home / 92.79-128-61.72

Finding the Fourth Proportional to 92.79, 128 and 61.72

Calculator

Solution

The fourth proportional to 92.79, 128 and 61.72 is: 85.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    92.79 : 128 = 61.72 : x
  2. Step 2: Convert to fraction form
    92.79/128 = 61.72/x
  3. Step 3: Cross multiply
    92.79x = 128 × 61.72
  4. Step 4: Simplify right side
    92.79x = 7,899.52
  5. Step 5: Solve for x
    x = 7,899.52/92.79
  6. Step 6: Final answer
    x = 85.14

Related Problems

Find fourth proportional to 46.39, 64 and 30.86
Half scale
Find fourth proportional to 185.57, 256 and 123.43
Double scale
Find fourth proportional to 93.79, 129.38 and 62.72
Similar ratio
Find fourth proportional to 139.18, 192 and 92.57
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.