Home / 489.71-675.81-279.89

Finding the Fourth Proportional to 489.71, 675.81 and 279.89

Calculator

Solution

The fourth proportional to 489.71, 675.81 and 279.89 is: 386.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    489.71 : 675.81 = 279.89 : x
  2. Step 2: Convert to fraction form
    489.71/675.81 = 279.89/x
  3. Step 3: Cross multiply
    489.71x = 675.81 × 279.89
  4. Step 4: Simplify right side
    489.71x = 189,151.62
  5. Step 5: Solve for x
    x = 189,151.62/489.71
  6. Step 6: Final answer
    x = 386.25

Related Problems

Find fourth proportional to 244.86, 337.91 and 139.94
Half scale
Find fourth proportional to 979.43, 1,351.62 and 559.78
Double scale
Find fourth proportional to 490.71, 677.19 and 280.89
Similar ratio
Find fourth proportional to 734.57, 1,013.72 and 419.83
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.