What is the formula for finding the square inch area of an oval?

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Discussion Overview

The discussion revolves around finding a formula for calculating the surface area of an oval, with specific interest in applications such as throttle body blades in vehicles. Participants explore various mathematical shapes related to ovals, including ellipses and ellipsoids, and propose different formulas and constants for area calculations.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested, Mathematical reasoning

Main Points Raised

  • One participant suggests a formula L x W x 0.80 for calculating the area of an oval.
  • Another participant clarifies that the term "oval" is not precisely defined and references ellipsoids and their complex surface area calculations.
  • A different formula A = \frac{\pi}{2} W(W + 2L) is proposed, assuming the oval consists of a half circle and a half ellipse.
  • It is noted that the area of an ellipse can be calculated using the formula lw\pi/4, while the surface area of an ellipsoid is more complex.
  • A participant expresses a need for specific measurements to calculate the surface area of a throttle body blade, indicating a practical application of the discussion.
  • Another participant highlights the ambiguity of the term "oval" and suggests that if a throttle body blade fits snugly in a cylinder, it can be treated as an ellipse, leading to a formula closer to (L x W x 0.785).
  • There are inquiries about finding the area of a D-shaped port, with suggestions to multiply dimensions by constants like 0.75 or 0.8, depending on the shape's characteristics.

Areas of Agreement / Disagreement

Participants express differing views on the definition of an "oval" and the appropriate formulas for calculating area, indicating that multiple competing views remain without consensus.

Contextual Notes

The discussion reveals limitations in the definitions of "oval" and the assumptions underlying the proposed formulas, as well as the dependence on specific measurements for practical applications.

5.0stang
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I am trying to find a simple formula for finding the surface area in square inches of an oval.

L x W x .80?

Thanks for any help!
 
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? I get something neat:

A = \frac{\pi}{2} W(W + 2L)

With W and L being measured in inches.

That's supposing that an oval consists of a half circle and a half ellipse.
 
Last edited:
The area of an ellipse (two-dimensional "flattened" circle) is \scriptstyle{lw}\pi/4.

The surface area of an ellipsoid (three dimensional "flattened" sphere) is more complex; see the formula linked above.
 
Thanks for the links! I am not a math whiz...lol.

I am trying to find the surface area of a "oval" throttle body blade on a EFI vehicle?

What measurements will I need?
 
The difficulty here stang is that an "oval" is not really a precisely defined mathematical entity. See http://mathworld.wolfram.com/Oval.html

Various well defined shapes such as ellipses and cycloids are "oval" like, but other mathematical forms could also be considered as oval, In other words the term "oval" is a little too broad to give an actual formula for surface area.

BTW. If the throttle body blade happens to fit snugly, at an oblique angle, inside a cylinder then it is in fact exactly an ellipse. As GRG has already pointed out the area of an ellipse is length times breadth times Pi divide 4. This is actually fairly close to what you originally guessed (L x W x 0.8), but it's actually closer to (L x W x 0.785).
 
Last edited:
Okay, guys, resurrecting an old thread.

How can one find the area of a D shaped port?

Multiply the long side of the D, and the width, and then multiply by .75?
 
5.0stang said:
How can one find the area of a D shaped port?

Multiply the long side of the D, and the width, and then multiply by .75?

If it's a semicircular D, then the constant will be pi/4 ~= 0.7854. If there is a semicircle, then a (short) straight segment along the top and bottom, then the constant will be somewhat larger -- perhaps 0.8?
 

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