Areas q_a

course Mth 173

assignment #001001. Areas

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qa areas volumes misc

06-12-2007

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18:40:24

`q001. There are 11 questions and 7 summary questions in this assignment.

What is the area of a rectangle whose dimensions are 4 m by 3 meters.

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RESPONSE -->

The area of a rectangle whose dimensions are 4m by 3m = 12 square meters.

confidence assessment: 3

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18:41:00

`q002. What is the area of a right triangle whose legs are 4.0 meters and 3.0 meters?

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RESPONSE -->

confidence assessment: 3

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18:44:44

`q003. What is the area of a parallelogram whose base is 5.0 meters and whose altitude is 2.0 meters?

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RESPONSE -->

A parallelogram whose base is 5.0 m and whose altitude is 2.0m has an area of 10.0 m^2

confidence assessment: 3

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18:47:53

`q004. What is the area of a triangle whose base is 5.0 cm and whose altitude is 2.0 cm?

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RESPONSE -->

The area of a triangle whose base is 5.0cm and whose altitude is 2.0cm is 5cm.

confidence assessment: 3

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18:48:58

`q005. What is the area of a trapezoid with a width of 4.0 km and average altitude of 5.0 km?

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RESPONSE -->

I must remember to include my units squared.

confidence assessment: 3

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18:59:06

`q006. What is the area of a trapezoid whose width is 4 cm in whose altitudes are 3.0 cm and 8.0 cm?

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RESPONSE -->

The area of a trapezoid with a width of 4cm, and altitudes of 3.0cm and 8.0 cm is 22.

Area of a trapezoid: 1/2 * h (a+b)=

1/2 * 4cm (3.0cm + 8.0cm)=

22cm^2

confidence assessment: 2

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18:59:20

`q007. What is the area of a circle whose radius is 3.00 cm?

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RESPONSE -->

confidence assessment: 3

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19:15:36

`q008. What is the circumference of a circle whose radius is exactly 3 cm?

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RESPONSE -->

The circumference of a circle that has a radius of 3 cm is 18.85cm.

confidence assessment: 3

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19:17:23

`q009. What is the area of a circle whose diameter is exactly 12 meters?

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RESPONSE -->

37.7cm^2 is the area of a circle whose diameter is 12.

confidence assessment: 2

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19:35:57

`q010. What is the area of a circle whose circumference is 14 `pi meters?

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RESPONSE -->

The area of a circle whose circumference is 14 pi meters = 87 pi meters.

confidence assessment: 0

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20:04:19

Knowing that A = pi r^2 we solve for r. We first divide both sides by pi to obtain A / pi = r^2. We then reverse the sides and take the square root of both sides, obtaining r = sqrt( A / pi ).

Note that strictly speaking the solution to r^2 = A / pi is r = +-sqrt( A / pi ), meaning + sqrt( A / pi) or - sqrt(A / pi). However knowing that r and A are both positive quantities, we can reject the negative solution.

Now we substitute A = 78 m^2 to obtain

r = sqrt( 78 m^2 / pi) = sqrt(78 / pi) m.{}

Approximating this quantity to 2 significant figures we obtain r = 5.0 m.

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RESPONSE -->

I entered a radius of 4.98m, but i accidently hit the next question button.

self critique assessment: 2

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20:11:02

`q012. Summary Question 1: How do we visualize the area of a rectangle?

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RESPONSE -->

We could vizualize the area of a rectanlge by multiplying the length and width of the rectangle. We could also vizualize the area by imagining the entire rectangle composed of tiny boxes. Example: For a length of 4"" and a width of 3"", we could visualize the rectangle filled with tiny boxes stacked four wide and three deep. Giving us an answer of 12"" or boxes.

confidence assessment: 2

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20:14:42

`q013. Summary Question 2: How do we visualize the area of a right triangle?

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RESPONSE -->

We visualize the area of a right triangle by thinking of it as a square cut diagonally. Giving us the formula of 1/2*b*h.

confidence assessment: 1

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20:15:30

`q014. Summary Question 3: How do we calculate the area of a parallelogram?

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RESPONSE -->

Area = b*h

confidence assessment: 3

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20:18:25

`q015. Summary Question 4: How do we calculate the area of a trapezoid?

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RESPONSE -->

We calculate the area of a trapezoid by: 1/2* height * (length a + length b).

confidence assessment: 2

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20:19:35

`q016. Summary Question 5: How do we calculate the area of a circle?

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RESPONSE -->

We calculate the area of a circle by taking pi and multiplying it by the radius squared.

confidence assessment: 2

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20:20:32

`q017. Summary Question 6: How do we calculate the circumference of a circle? How can we easily avoid confusing this formula with that for the area of the circle?

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RESPONSE -->

To calculate the circumference of a circle, we take 2* pi * radius.

confidence assessment: 2

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20:22:25

`q018. Explain how you have organized your knowledge of the principles illustrated by the exercises in this assignment.

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RESPONSE -->

I have learned to break down each step of a formula and translate it. Which helps in the memorization and understanding of the formula.

confidence assessment: 2

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Areas q_a

You did well on these questions. Let me know if you have questions.