Quadrangular 64724

The decorative object has a quadrangular pyramid shape. Its base edge is 0.7 dm, and its side edge is 1.4 dm long. Calculate its height.

Correct answer:

h =  1.3096 dm

Step-by-step explanation:

$$\begin{gathered} a=0.7\text{dm} \\ s=1.4\text{dm} \\ b=\sqrt{2}\cdot a/2=\sqrt{2}\cdot 0.7/2\doteq 0.495\text{dm} \\ {s}^2=b^2+h^2 \\ h=\sqrt{s^2-b^2}=\sqrt{1.4^2-0.495^2}=1.3096\text{dm} \end{gathered}$$

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