Finding Gradient: Tips & Techniques

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Discussion Overview

The discussion revolves around identifying the type of plane figure represented by a given area and calculating the area of a trapezoid using its dimensions. Participants explore the application of geometric formulas and the derivation of a linear equation based on the trapezoid's properties.

Discussion Character

  • Homework-related
  • Mathematical reasoning

Main Points Raised

  • Some participants inquire about the type of plane figure, suggesting it is unspecified initially.
  • Others assert that the figure is a trapezoid and provide the area formula for a trapezoid, including its parameters.
  • One participant presents a calculation using the trapezoid area formula, substituting known values to derive an equation for the unknown base.
  • A later reply completes the calculation, solving for the unknown base and deriving the slope and equation of the line based on the trapezoid's properties.

Areas of Agreement / Disagreement

Participants generally agree that the figure in question is a trapezoid, but there is no explicit consensus on the initial identification of the figure as unspecified.

Contextual Notes

The discussion includes assumptions about the dimensions of the trapezoid and the application of the area formula, but does not resolve potential ambiguities in the problem statement.

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What type of plane figure is the given area?
 
MarkFL said:
What type of plane figure is the given area?

It does not specify
 
Yazan975 said:
It does not specify

We can see that it is a trapezoid. A formula for the area \(A\) of a trapezoid is:

$$A=\frac{h}{2}(B+b)$$

where:

$$h$$ is the height (we see is is 5 units)

$$B$$ is the "big base" (this is unknown)

$$b$$ is the "little base" (we see this is 2 units)

So, plugging everything we know into the area formula, we obtain:

$$\frac{35}{2}=\frac{5}{2}(B+2)$$

Solve this for \(B\)...what do you get?
 
MarkFL said:
We can see that it is a trapezoid. A formula for the area \(A\) of a trapezoid is:

$$A=\frac{h}{2}(B+b)$$

where:

$$h$$ is the height (we see is is 5 units)

$$B$$ is the "big base" (this is unknown)

$$b$$ is the "little base" (we see this is 2 units)

So, plugging everything we know into the area formula, we obtain:

$$\frac{35}{2}=\frac{5}{2}(B+2)$$

Solve this for \(B\)...what do you get?

Thanks! Big help. I got the answer
 
Yazan975 said:
Thanks! Big help. I got the answer

For the benefit of others who may read this thread, I will complete the problem. This will make the thread more useful (hint hint).

I posted:

$$\frac{35}{2}=\frac{5}{2}(B+2)$$

Multiply through by \(\dfrac{2}{5}\):

$$7=B+2$$

Subtract through by 2 and arrange as:

$$B=5$$

From this, we may conclude that the point \((5,5)\) is on the line, and we also know \((0,2)\) is on the line (the \(y\)-intercept), and so the slope \(m\) of the line is:

$$m=\frac{5-2}{5-0}=\frac{3}{5}$$

Armed with the slope and intercept, we may give the equation of the line as:

$$y=\frac{3}{5}x+2$$
 

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