Books Books To find the area of a trapezoid. RULE. Multiply half the sum of the two parallel sides by the perpendicular distance between them : the product will be the area. A System of Geometry and Trigonometry: Together with a Treatise on Surveying ... - Page 33
by Abel Flint - 1804 - 168 pages ## Practical Mechanical Drawing and Machine Design, Self Taught ...

Charles Westinghouse - Machine design - 1906 - 168 pages
...by the perpendicular height. Parallelogram : Area=D x H To find the area of a trapezoid— Fig. 92. Multiply half the sum of the two parallel sides by the perpendicular distance between the sides. Polygon: Area= No. of si Trapezoid: Area= (HE+D) To find the area of an equilateral triangle... ## Lessons in Practical Hygiene for Use in Schools

Alice Ravenhill - Hygiene - 1907 - 762 pages
...of a triangle. Base x perpendicular height, divide by 2. To find the area of a trapezoid. Multiply the sum of the two parallel sides by the perpendicular distance between them, divide by 2. To find the area of any rectilinear figure. Divide the figure into triangles by lines... ## Field and Colliery Surveying: A Primer Designed for the Use of Students of ...

Thomas Aloysius O'Donahue - Mine surveying - 1911 - 288 pages
...the area. Let S = |(AB + BC + CA). (12) (Fig. 63) Area = VS(S - AB)(S - BC)(S - OA). Trapezoid. — Multiply half the sum of the two parallel sides by the perpendicular distance between them, and the product will be the area. B (13) (Fig. 64) Area = |(AD + BC) x DE. FIG. ' B Fio. 64. If the... ## Printers' Arithmetic

Charles Lingle Woodfield - Arithmetic - 1917 - 154 pages
...Surfaces I. To find the area of a square or a rectangle: Rule.— Multiply the length by the width. IL To find the area of a trapezoid: Rule. — Multiply half the sum of the parallel sides by the altitude. III. To find the area of a triangle: Rule. — Multiply the base by... ## Builders' Reliable Estimator and Contractors' Guide: A Complete Guide for ...

Frederick Thomas Hodgson - 1917 - 716 pages
...perpendiculars, de and bf, 18 and l(i feet? Problem IV. — To find the area of a trapezoid. Rule. — Multiply the sum of the two parallel sides by the perpendicular distance between them, and half the product will be the area. Example i. — Required the area of the trapezoid, abed, having... ## Plating and Boiler-making: A Practical Handbook for Workshop Operations ...

Joseph Gregory Horner - 1920 - 418 pages
...is a rectilineal figure which has two sides only parallel. Its area is obtained thus : — Multiply the sum of the two parallel sides by the perpendicular distance between them, and half the product will be the area. Polygons. — Lastly, the area of any rectilineal polygonal... ## The Architects' and Builders' Handbook: Data for Architects, Structural ...

Frank Eugene Kidder - Architecture - 1921 - 1944 pages
...the product by 2. Thus, ab X (ce + di) To find the area of a trape zoíd (Fig. j8). Rule. Multiply the sum of the two parallel sides by the perpendicular distance between them and divide the product by 2. To compute the area of an irregular polygon. Part 1 To find the are«... 