Step 1: Find the lengths of the sides

          Step 1: Add all the terms in the ratio      

                        EXAMPLE:  3 + 4 + 5 = 12

            Step 2: Divide this sum by each term in the ratio

                          EXAMPLE; \frac{3}{12},

                                               \frac{4}{12},

                                                 \frac{5}{12}.

          Step 3: Multiply the fraction with the given perimeter. To find triangle sides

                      EXAMPLE:     \frac{3}{12}* 30 =  7.5

                                               \frac{4}{12}* 30 = 10

                                               \frac{5}{12}* 30 = 12.5

Step 2: Recall the area formula of the triangle.

              FORMULA: \sqrt{s(s - a)(s - b)(s - c)}

            Where a, b and c are the sides of the triangle and

                s = half the perimeter = \frac{1}{2} (a+b+c)

Step 3: Calculate the "s" value

          EXAMPLE: \frac{1}{2} (a+b+c)

                               \frac{1}{2} (3 + 4 + 5)

                            s = 6

Step 4: Substitute all the values in the area of the triangle formula

            EXAMPLE: A = \sqrt{s(s - a)(s - b)(s - c)}

                                A = \sqrt{ 6 (6 - 3)(6 - 4)(6 - 5)}

Step 5: Do some calculations to find area.

          EXAMPLE:    A = \sqrt{ 6 (3)(2)(1)}

                              A = \sqrt{36}

                              A = 6