Home / 287.18-430.80-81.76

Finding the Fourth Proportional to 287.18, 430.80 and 81.76

Calculator

Solution

The fourth proportional to 287.18, 430.80 and 81.76 is: 122.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.18 : 430.80 = 81.76 : x
  2. Step 2: Convert to fraction form
    287.18/430.80 = 81.76/x
  3. Step 3: Cross multiply
    287.18x = 430.80 × 81.76
  4. Step 4: Simplify right side
    287.18x = 35,222.21
  5. Step 5: Solve for x
    x = 35,222.21/287.18
  6. Step 6: Final answer
    x = 122.65

Related Problems

Find fourth proportional to 143.59, 215.40 and 40.88
Half scale
Find fourth proportional to 574.36, 861.60 and 163.52
Double scale
Find fourth proportional to 288.18, 432.30 and 82.76
Similar ratio
Find fourth proportional to 430.77, 646.20 and 122.64
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.