Home / 980-1,353-631.30

Finding the Fourth Proportional to 980, 1,353 and 631.30

Calculator

Solution

The fourth proportional to 980, 1,353 and 631.30 is: 871.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    980 : 1,353 = 631.30 : x
  2. Step 2: Convert to fraction form
    980/1,353 = 631.30/x
  3. Step 3: Cross multiply
    980x = 1,353 × 631.30
  4. Step 4: Simplify right side
    980x = 854,148.90
  5. Step 5: Solve for x
    x = 854,148.90/980
  6. Step 6: Final answer
    x = 871.58

Related Problems

Find fourth proportional to 490, 676.50 and 315.65
Half scale
Find fourth proportional to 1,960, 2,706 and 1,262.60
Double scale
Find fourth proportional to 981, 1,354.38 and 632.30
Similar ratio
Find fourth proportional to 1,470, 2,029.50 and 946.95
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.