sides of a triangle

**silencecloak** · May 15th 2008, 11:14 PM

i know side AC = $\sqrt{52}$

but thats as far as my brain will take me right now, thanks

**Moo** · May 15th 2008, 11:28 PM

Hello,

Originally Posted by silencecloak

i know side AC = $\sqrt{52}$

but thats as far as my brain will take me right now, thanks

How much do you know about trigonometry ?

$\cos B=\frac{BC}{AB} \ \begin{array}{c} \leftarrow \text{adjacent} \\ \leftarrow \text{hypotenuse} \end{array}$ , considering triangle ABC.

$\cos B=\frac{\color{red}BD}{BC} \ \begin{array}{c} \leftarrow \text{adjacent} \\ \leftarrow \text{hypotenuse} \end{array}$ , considering triangle BCD.

$\implies \frac{\color{red}BD}{BC}=\frac{BC}{AB}$

Does it help you ?

**silencecloak** · May 15th 2008, 11:44 PM

Thank you i appreciate your help as always

**Soroban** · May 16th 2008, 06:17 AM

Hello, silencecloak!

28. Find $BD.$

Code:

            C
            *
           *|  *
          * |     *  12
         *  |        *
        *   |           *
       *    |              *
    A *  *  *  *  *  *  *  *  * B
            D        x
      : - - - - 14  - - - - - :

There is a theorem which covers this very situation,
. . but we don't need it.

Let $x \,=\,BD$

Since $\Delta CDB \sim \Delta ACB\!:\;\;\frac{x}{12}\:=\:\frac{12}{14} \quad\Rightarrow\quad\boxed{ x \:=\:\frac{72}{7}}$

Thread: sides of a triangle

LinkBack

Thread Tools

Display

sides of a triangle

Similar Math Help Forum Discussions

Sides of triangle: a= p^2+p+1, b=p^2+2p, c=2p+1

sides of triangle

The sides of a triangle are given by the lines........find the area of this triangle

three sides of a triangle

A triangle and its sides

Search Tags