面積の公式 - Math.com

Area Formulas Home | Teacher | Parents | Glossary | About Us Email this page to a friend Resources · Cool Tools · Formulas & Tables · References · Test Preparation · Study Tips · Wonders of Math Search Area Formulas ( Math | Geometry | Area Formulas) ( pi = = 3.141592...) Area Formulas Note: "ab" means "a" multiplied by "b". "a 2 " means "a squared", which is the same as "a" times "a". Be careful!! Units count. Use the same units for all measurements. Examples square = a 2 rectangle = ab parallelogram = bh trapezoid = h/2 (b 1 + b 2 ) circle = pi r 2 ellipse = pi r 1 r 2 triangle = one half times the base length times the height of the triangle equilateral triangle = triangle given SAS (two sides and the opposite angle) = (1/2) a b sin C triangle given a,b,c = [s(s-a)(s-b)(s-c)] when s = (a+b+c)/2 (Heron's formula) regular polygon = (1/2) n sin(360°/n) S 2 when n = # of sides and S = length from center to a corner Units Area is measured in "square" units. The area of a figure is the number of squares required to cover it completely, like tiles on a floor. Area of a square = side times side. Since each side of a square is the same, it can simply be the length of one side squared. If a square has one side of 4 inches, the area would be 4 inches times 4 inches, or 16 square inches. (Square inches can also be written in 2 .) Be sure to use the same units for all measurements. You cannot multiply feet times inches, it doesn't make a square measurement. The area of a rectangle is the length on the side times the width. If the width is 4 inches and the length is 6 feet, what is the area? NOT CORRECT .... 4 times 6 = 24 CORRECT .... 4 inches is the same as 1/3 feet. Area is 1/3 feet times 6 feet = 2 square feet. (or 2 sq. ft., or 2 ft 2 ). Contact us | Advertising & Sponsorship | Partnership | Link to us © 2000-2023 Math.com. All rights reserved. Legal Notices . Please read our Privacy Policy .