Home / 102.78-141.75-65.91

Finding the Fourth Proportional to 102.78, 141.75 and 65.91

Calculator

Solution

The fourth proportional to 102.78, 141.75 and 65.91 is: 90.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.78 : 141.75 = 65.91 : x
  2. Step 2: Convert to fraction form
    102.78/141.75 = 65.91/x
  3. Step 3: Cross multiply
    102.78x = 141.75 × 65.91
  4. Step 4: Simplify right side
    102.78x = 9,342.74
  5. Step 5: Solve for x
    x = 9,342.74/102.78
  6. Step 6: Final answer
    x = 90.90

Related Problems

Find fourth proportional to 51.39, 70.88 and 32.96
Half scale
Find fourth proportional to 205.56, 283.50 and 131.82
Double scale
Find fourth proportional to 103.78, 143.13 and 66.91
Similar ratio
Find fourth proportional to 154.17, 212.63 and 98.87
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.