From 052a0dd1b420266bc282c9538f424eb8dded8672 Mon Sep 17 00:00:00 2001 From: joesvetz <30700890+joesvetz@users.noreply.github.com> Date: Thu, 14 Mar 2019 09:43:28 -0700 Subject: [PATCH] Expansion of Area of Triangles (#29909) Fixed a small type-o and added information about the area of obtuse triangles. --- guide/english/mathematics/area-of-triangles/index.md | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/guide/english/mathematics/area-of-triangles/index.md b/guide/english/mathematics/area-of-triangles/index.md index 7889012e0e..47488d53a0 100644 --- a/guide/english/mathematics/area-of-triangles/index.md +++ b/guide/english/mathematics/area-of-triangles/index.md @@ -10,11 +10,11 @@ The area of a triangle can be calculated by multiplying one half by the base * h For example, if you have a triangle that is 3cm on the base and 4cm in height, then you can work out the area: -Areaa= .5 * 3 * 4 = 6cm² +Area = .5 * 3 * 4 = 6cm² #### Terminology -* Base (b) - The length of one side of the triangle. +* Base (b) - The length of one side of the triangle (note: the side chosen for the base must always have angles of 90 degrees or less on both ends) * Height (h) - The length of a line perpendicular with the base to the opposite point of the triangle. #### Formula @@ -26,6 +26,14 @@ For example in the image above, Area = 0.5 * a * h +#### Important information about Obtuse Triangles + +An obtuse triangle is one that has an internal angle of more than 90 degrees, like the one pictured below: + + + +In this case, the base must be side 'BC' and not 'AB' or 'CA' (the height would be a perpendicular line from the base to point 'A'). If the measurement of the height is not known, it would have to be measured, or it would need to be calculated using trigonometry. + ### More Information * [Area of Triangles](http://www.onlinemathlearning.com/area-triangle.html)