Question

In a ∆ABC angle A=90° AC÷BC=0.75 and BC=7cm find are of a∆ABC

Answer 1

Answer:   12.15375 cm²

Step-by-step explanation:

BC = 7 cm

  AC / BC = 0.75

or, AC / 7 = 0.75

or, AC      =  0.75×7 = 5.25 cm

∴ AB = √(BC² - AC²)

        = √(49 - 27.5625)

        = √21.4375

        ≈ 4.63

Hence the area of the ΔABC = 1/2 ×AB × AC

                                                = 1/2 × 4.63 × 5.25 cm²

                                                = 1/2 × 24.3075 cm²

                                                = 12.15375 cm²