Conic Sections

Definition
Conic sections can be defined as the locus of point that moves so that the ratio of its distance from a fixed point called the focus to its distance from a fixed line called the directrix is constant. The constant ratio is called the eccentricity of the conic.
 

06 Circular arcs inside and tangent to an equilateral triangle

Example 06
The figure shown below is an equilateral triangle of sides 20 cm. Three arcs are drawn inside the triangle. Each arc has center at one vertex and tangent to the opposite side. Find the area of region enclosed by these arcs. The required area is shaded as shown in the figure below.
 

Circular arcs inside a triangle

 

05 Three identical cirular arcs inside a circle

Example 05
Circular arcs of radii 10 cm are described inside a circle of radius 10 cm. The centers of each arc are on the circle and so arranged so that they are equally distant from each other. Find the area enclosed by three arcs shown as shaded regions in the figure.
 

04 Four overlapping semi-circles inside a square

Example 04
The figure shown below consists of arcs of four semi-circles with centers at the midpoints of the sides of a square. The square measures 20 cm by 20 cm. Find the area bounded by these circular arcs shaded in the figure shown.
 

03 Area enclosed by pairs of overlapping quarter circles

Example 03
The shaded regions in the figure below are areas bounded by two circular arcs. The arcs have center at the corners of the square and radii equal to the length of the sides. Calculate the area of the shaded region.
 

02 Area bounded by arcs of quarter circles

Three Different Ways of Finding the Area Bounded by Arcs of Quarter Circles

Example 02
Arcs of quarter circles are drawn inside the square. The center of each circle is at each corner of the square. If the radius of each arc is equal to 20 cm and the sides of the square are also 20 cm. Find the area common to the four circular quadrants. See figure below.
 

Area common to four quarter circles

 

01 Arcs of quarter circles

Example 01
The figure shown below are circular arcs with center at each corner of the square and radius equal to the side of the square. It is desired to find the area enclosed by these arcs. Determine the area of the shaded region.
 

Intersection of circular quadrants

 

016 Radius of the sphere circumscribing a regular triangular pyramid

Example 016
Find the area of the surface and the volume of the sphere circumscribed about a regular tetrahedron of edge 25 cm. See Figure 015.
 

Sphere circumscribed about a regular tetrahedron

 

015 Two unequal balls inside the cylinder

Example 015
Two balls, one 15 cm in diameter and the other 10 cm in diameter, are placed in a cylindrical jar 20 cm in diameter, as shown in Figure 014. Find the volume of water necessary to cover them.
 

016-balls-inside-cylinder.gif

 

014 Water poured into a jar of marbles

Example 014
A boy who had discovered that 20 mm marbles fitted snugly into the bottom of a cylindrical jar, dropped in a fourth on top of the three and poured water enough into the jar to just cover them. How much water did he use?
 

Pages

Subscribe to MATHalino RSS