Triangle base perimeter

In an isosceles triangle, the side a=b= 21 cm, and the triangle's height is 19 cm. Find out the base and perimeter of the triangle (sketch, calculation, answer).

Final Answer:

c =  17.8885 cm
o =  59.8885 cm

Step-by-step explanation:

$$\begin{gathered} a=21\text{cm} \\ h=19\text{cm} \\ b=a=21\text{cm} \\ {a}^2=h^2+(c/2{)}^2 \\ c=2\cdot \sqrt{a^2-h^2}=2\cdot \sqrt{21^2-19^2}=8\sqrt{5}=17.8885\text{cm} \end{gathered}$$

$o=a+b+c=21+21+17.8885=59.8885\text{cm}$

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