balkan wrote:

Hi there!

I just would like to ask a question about the scope of GMAT in geometry.

How far does GMAT go in geometry?

Do I need to know anything about spheres, cones and pyramids or should I just worry about circles and cylinders?

Thanks!

Hi Balkan,

As far as what topics of Mathematics are covered in the GMAT, your best bet is to open

the Official Guide (11th, 12th or 13th Edition) and go thru Chapter 4.0 Math Review.

For geometry, reference section 4.3 Geometry, pages 107, p127 thru 139 (

OG 12th Edition)

'Geometry is limited primarily to measurement and intuitive geometry or spatial visualization. Extensive knowledge of theorems and the ability to construct proofs, skills that are usually developed in a formal geometry course, are not tested. The topics included in this section are the following:

1. Lines

2. intersecting Lines and Angles

3. Perpendicular lines

4. Parallel Lines

5. Polygons (Convex)

6. Triangles

7. Quadrilaterals

8. Circles

9. Rectangular Solids and Cylinders

10. Coordinate Geometry'I have not yet seen an 'official' GMAT problem with spheres, cones or pyramids that could not be 'reduced' to a 2D problem with circle(s), square(s) or triangles(s).

For example:

how-many-spheres-of-a-1-foot-radius-can-fit-in-a-8x10x12-37862.htmlNow...it would hurt your general knowledge and/or personal confidence to know the following formulas:

Sphere:Surface (Sphere) = 4*pi*R^2Volume (Sphere) = \frac{4}{3}*pi*R^3http://en.wikipedia.org/wiki/Spherevolume-of-a-sphere-84970.htmlsphere-inside-cube-35637.htmlmethod-to-solve-3-spheres-of-dough-problem-107119.htmlps-crystal-spheres-34671.htmlCone:Surface (Cone) = pi*R*(R+L)where

R is the radius of the circle at the bottom of the cone and

L is the lateral height of the cone (given by the Pythagorean theorem

L=\sqrt{R^2 + h^2} where

h is the height of the cone).

Volume (Cone) = \frac{1}{3}*B*hwhere

B is the area of the base and

h the height (the perpendicular distance from the base to the apex).

http://en.wikipedia.org/wiki/Cone_(geometry)#Geometry

cones-and-spheres-on-gmat-96751.htmlPyramid:Volume (Pyramid) = \frac{1}{3}*B*h (same formula as for the Cone)

Surface (Pyramid) = B + \frac{(P*L)}{2}where

B is the base area,

P is the base perimeter and

L is the slant height

L=\sqrt{R^2 + h^2} where

h is the pyramid altitude and R is the inradius of the base.

http://en.wikipedia.org/wiki/Pyramid_(geometry)#Volume

find-the-volume-of-a-pyramid-13904.html _________________

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