If AD = 5.1cm, find the height (in cm) of the triangle.

I. AC = 15 cm

II. h = 7.4 cm

Step-by-step explanation:

I. Determination of AC

AB = 9 cm

BC = 12 cm

AC =?

The length AC can be obtained by using pythagoras theory as illustrated below:

AC² = AB² + BC²

AC² = 9² + 12²

AC² = 81 + 144

AC² = 225

Take the square root of both side

AC = √225

AC = 15 cm

II. Determination of the height.

AB = 9 cm

AD = 5.1 cm

BD = h =?

The height of the triangle can be obtained by using pythagoras theory as illustrated below:

AB² = AD² + BD²

9² = 5.1² + h²

81 = 26.01 + h²

Collect like terms

h² = 81 – 26.01

h² = 54.99

Take the square root of

h = √54.99

h = 7.4 cm