Ratio of sides

The triangle has a circumference of 21 cm, and the length of its sides is in a ratio of 6:5:3. Find the length of the longest side of the triangle in cm.

Correct answer:

a =  9 cm
b =  7.5 cm
c =  4.5 cm

Step-by-step explanation:

$$\begin{gathered} o=21\text{cm} \\ o=a+b+c=21 \\ a=6x \\ b=5x \\ c=3x \\ 6x+5x+3x=o \\ 6x+5x+3x=21 \\ 6\cdot x+5\cdot x+3\cdot x=21 \\ 14x=21 \\ x=\frac{21}{14}=1.5 \\ x=\frac{3}{2}=1.5 \\ a=6\cdot x=6\cdot 1.5=9\text{cm} \end{gathered}$$

Try calculation via our triangle calculator.

$b=5\cdot x=5\cdot 1.5=7.5\text{cm}$

$c=3\cdot x=3\cdot 1.5=4.5\text{cm}$

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