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Curved surfaces . Learning outcomes. To be able to identify a chord To describe the pressed screed method To identify a secant line . B. r = 90 º. A. C. A Radius Rod is set across the diameter of the curve ,so it has three equal radius measurements as shown (A,B,C).
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Learning outcomes • To be able to identify a chord • To describe the pressed screed method • To identify a secant line
B r = 90º A C A Radius Rod is set across the diameter of the curve ,so it has three equal radius measurements as shown (A,B,C). Forming accurate curved surfaces requires the same basic principles as running a semi - circular arch.
B A C The pressed screed method. Dots set from the radius rod and then plumbed up. Screeds between thedots. The dots are set from a radius rod. B r = 90º C A
Screeds need to be applied once the dots have set enough and pressed into a curve with the template, hence the name the pressed screed method . This method can also be used to float the interior of a niche. B r = 90º C A
Y X Columns Cornices and Curves Columns Cornices and Curves Columns Cornices and Curves Chapter 7 page 16 Chapter 7 page 16 Chapter 7 page 16 Form a concave curved wall Form a concave curved wall Form a concave curved wall Chords are equidistant from the centre if and only if their lengths are equal. Chords are equidistant from the centre if and only if their lengths are equal. Chords are equidistant from the centre if and only if their lengths are equal. A chord of a curve is a geometric line segment whose endpoints X ,Y both lie on the curve. A chord of a curve is a geometric line segment whose endpoints X ,Y both lie on the curve. A chord of a curve is a geometric line segment whose endpoints X ,Y both lie on the curve. A chord of a curve is a geometric line segment whose endpoints X ,Y both lie on the curve. A secant or a secant line is the line extension of a chord A secant or a secant line is the line extension of a chord. A secant or a secant line is the line extension of a chord A secant or a secant line is the line extension of a chord. A secant or a secant line is the line extension of a chord. A secant or a secant line is the line extension of a chord A secant or a secant line is the line extension of a chord. Chords are equidistant from the centre if and only if their lengths are equal. The centre for a concave curved wall can be determined by bisecting two chords Y Y Y X X X
Task • Sketch a circle and show the chord and secant line
Recap • What is the pressed screed method • How do we find the cord of a circle • What is a secant line