Home / 102.30-153.05-78

Finding the Fourth Proportional to 102.30, 153.05 and 78

Calculator

Solution

The fourth proportional to 102.30, 153.05 and 78 is: 116.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.30 : 153.05 = 78 : x
  2. Step 2: Convert to fraction form
    102.30/153.05 = 78/x
  3. Step 3: Cross multiply
    102.30x = 153.05 × 78
  4. Step 4: Simplify right side
    102.30x = 11,937.51
  5. Step 5: Solve for x
    x = 11,937.51/102.30
  6. Step 6: Final answer
    x = 116.69

Related Problems

Find fourth proportional to 51.15, 76.52 and 39
Half scale
Find fourth proportional to 204.60, 306.09 and 156
Double scale
Find fourth proportional to 103.30, 154.54 and 79
Similar ratio
Find fourth proportional to 153.45, 229.57 and 117
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.