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The area of the surface of a sphere is equal to four times the area of the circle formed by a great circle of this sphere. The area of a segment of a parabola determined by a straight line cutting it is 4/3 the area of a triangle inscribed in this segment. For the proofs of these results, Archimedes used the method of exhaustion attributed to ...
Quarter-circular area [2] ... The points on the circle + = and in the first quadrant = Semicircular arc: The points on the ...
Signs of trigonometric functions in each quadrant. In the above graphic, the words in quotation marks are a mnemonic for remembering which three trigonometric functions (sine, cosine, tangent and their reciprocals) are positive in each quadrant. The expression reads "All Science Teachers Crazy" and proceeding counterclockwise from the upper ...
A parabolic segment is the region bounded by a parabola and line. To find the area of a parabolic segment, Archimedes considers a certain inscribed triangle. The base of this triangle is the given chord of the parabola, and the third vertex is the point on the parabola such that the tangent to the parabola at that point is parallel to the chord.
The area of a triangle can be demonstrated, for example by means of the congruence of triangles, as half of the area of a parallelogram that has the same base length and height. A graphic derivation of the formula T = h 2 b {\displaystyle T={\frac {h}{2}}b} that avoids the usual procedure of doubling the area of the triangle and then halving it.
For example, a circle of radius 2, centered at the origin of the plane, may be described as the set of all points whose coordinates x and y satisfy the equation x 2 + y 2 = 4; the area, the perimeter and the tangent line at any point can be computed from this equation by using integrals and derivatives, in a way that can be applied to any curve.
The area of a shape can be measured by comparing the shape to squares of a fixed size. [2] In the International System of Units (SI), the standard unit of area is the square metre (written as m 2), which is the area of a square whose sides are one metre long. [3] A shape with an area of three square metres would have the same area as three such ...
Quadrats typically occupy an area of 0.25 m 2 and are traditionally square, but modern quadrats can be rectangular, circular, or irregular. [1] [2] A quadrat is suitable for sampling or observing plants, slow-moving animals, and some aquatic organisms. A photo-quadrat is a photographic record of the area framed by a quadrat.