Length of a side, possible triangle side

[Tsroll]

I have one question from my mathematics for machine technology book that has me stumped as well as my Father in-law, sister in-law and my accountant friend.

I wasn't sure if I was supposed to create a right triangle and use A² + B² = C²

Problem 18. B

http://i182.photobucket.com/albums/x11/darkamek/Mobile%20Uploads/0C5C92BD-3681-499C-AF27-9DE175F5EF68_zps7ltszocb.jpg

 

[Prove It]

I have one question from my mathematics for machine technology book that has me stumped as well as my Father in-law, sister in-law and my accountant friend.

I wasn't sure if I was supposed to create a right triangle and use A² + B² = C²

Problem 18. B

http://s182.photobucket.com/user/da...1-499C-AF27-9DE175F5EF68_zps7ltszocb.jpg.html

First of all, you have to notice that the triangle is isosceles. This is important as the calculations wouldn't work out otherwise.

To find A, you need to add 7 inches to HALF of the base of the triangle.

To find B, you need to find the height of the triangle (if you draw in the height you will create two right-angle triangles, and you can use Pythagoras). Once you have the height of the triangle, subtract it from 17.823 inches.

 

[pickslides]

As the triangle is isosceles I believe $A=7+0.5\times 30.263$

and $B=17.823 - h$ where $h$ is the height of the triangle. Have a go at finding it.

 

[Tsroll]

17.823 - √[(18.09)² - (30.263/2)²] = 7.909