Question

a triangle has an area of 90 cm square find the length of the base if the base is 3 more than height ​

Answer 1

Answer:

9cm

Step-by-step explanation:

Let us take the height as x

Since the base is 3 more than the height, base is x+3

Formula for finding area of a triangle: Area = 1/2 * base * height

                                                                  90 = 1/2 * (x+3) * x

       Only exchanging their sides            1/2 * (x+3) * x = 90

                                                                    x (x+3) = 90 * 2

                                                                    $x^{2}+3x=180\\x^{2}+3x-180=0$

                                                                    $x^{2}+15x-12x-180=0\\x(x+15)-12(x+15)=0\\(x-12)(x-15)=0$

                                                                    (x-12)=0 or (x+15) = 0

                                                                    x = 12 or x = - 15

Base = x + 3

Base = (12 - 3)cm or (-15 - 3)cm

Base = 9cm or -18cm

Since the side of a triangle cannot be negative the answer is 9cm