PREPARATION OF THE DESIGN 103 



ESTIMATING 



A CERTAIN knowledge of estimating is required of 

 a garden designer : not that he is contractor for 

 the work, but because his client generally requires 

 some idea of the cost before accepting a plan. 



A knowledge of the plain rules of arithmetic is 

 sufficient mathematical qualification for this 

 somewhat tedious process, and 

 it is also necessary to know the 

 simple methods of mensuration. 



A four-sided rectangular figure 

 needs its length and breadth mul- ' DlAGR ^ M 2 

 tiplied together to give its area, 

 and a right angled triangle is half that area. Thus 

 if the figure A B C D (Diagram 29) contains 24 sq. 

 ft., the triangle BCD contains 12 sq. ft. This is 

 sometimes expressed by saying that the area of a 

 triangle is equal to its base multiplied by half 

 the perpendicular in the example this is 6 X 2 

 =12. But seldom does one meet with convenient 

 rectangular figures, and surveys generally deal 

 in variously shaped triangles. The principle is, 

 however, the same, although a perpendicular may 

 have to be set up from base to apex. See Diagram 

 30, where the perpendicular, of which half the 

 height is to be used, is set up either within or 

 without the figure. By means of triangles the 

 area of any complicated figure can be built up to 

 its total. A five-sided figure may be reduced to a 



