Hypotenuse Of Roof Beams



GCSE Marks:

GCSE Text:
The design of the roof beams in a new building is shown in this diagram:

roof pythag.png

Calculate the length of side AB in the main triangle in the design.

This video was made when a school building was being constructed on site. KIER Construction kindly allowed a number of videos to be made so that students could grasp the use of Maths in the construction industry. Students very much enjoy seeing a professional (other than a teacher) talk about design, specification and mathematics, and it is a firm favourite. It is a conventional Pythagoras question, and accuracy can be specified by the teacher to include rounding skills either to a number of decimal places or significant figures.

Extension Ideas:
Teachers could extend the learning by considering:

  • Rounding to a variety of places/figures
  • Adding extra measurements to the diagram and requiring students to calculate an additional hypotenuse, or adding a hypotenuse and requiring students to calculate a side length. The diagonal brace to the right of the vertical side of the triangle is a good measurement to add (around 3.3m works well), and students can calculate the horizontal distance at the bottom. Alternatively provide the horizontal distance at the bottom right (around 1.95m works well) and ask students to calculate a second hypotenuse.

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