Hexagons!

Level pending

The regular hexagon above has side length 15 2 \dfrac{15}{\sqrt{2}}

Using the above diagram find the value of x x .


The answer is 9.

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

1 solution

Rocco Dalto
Nov 27, 2019

Using right A D G \triangle{ADG} in the diagram above we obtain:

A D 2 = ( 12 + x ) 2 + 3 2 = 153 + 24 x + x 2 = ( 15 2 ) 2 = 450 |\overline {\rm AD}|^2 = (12 + x)^2 + 3^2 = 153 + 24x + x^2 = (15\sqrt{2})^2 = 450

x 2 + 24 x 297 = 0 ( x + 33 ) ( x 9 ) = 0 x = 33 \implies x^2 + 24x - 297 = 0 \implies (x + 33)(x - 9) = 0 \implies x = -33 or x = 9 x = 9 .

Since x = 33 x = -33 is not a valid solution to this problem x 33 x = 9 \implies x \neq -33 \implies \boxed{x = 9} .

Did it the same way, i wonder about other approaches

Valentin Duringer - 12 months ago

Log in to reply

I'm not certain. I can look into it.

Rocco Dalto - 11 months, 4 weeks ago

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...