Home / 89-122.78-61.40

Finding the Fourth Proportional to 89, 122.78 and 61.40

Calculator

Solution

The fourth proportional to 89, 122.78 and 61.40 is: 84.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    89 : 122.78 = 61.40 : x
  2. Step 2: Convert to fraction form
    89/122.78 = 61.40/x
  3. Step 3: Cross multiply
    89x = 122.78 × 61.40
  4. Step 4: Simplify right side
    89x = 7,538.69
  5. Step 5: Solve for x
    x = 7,538.69/89
  6. Step 6: Final answer
    x = 84.70

Related Problems

Find fourth proportional to 44.50, 61.39 and 30.70
Half scale
Find fourth proportional to 178, 245.56 and 122.80
Double scale
Find fourth proportional to 90, 124.16 and 62.40
Similar ratio
Find fourth proportional to 133.50, 184.17 and 92.10
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.