Stuck on this maths question...

[Laurenkiernan0507]

Not sure if anyone could help me with this as I'm stuck.

Also with the workings out so I can understand? I keep doing working out that leads to the wrong answer.

 

[Deleted member 4993]

Not sure if anyone could help me with this as I'm stuck.

Also with the workings out so I can understand? I keep doing working out that leads to the wrong answer.

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Please share your work/thoughts about this assignment.

If I were to do this problem:

I would first calculate the total area of the "flower-beds" = 40 * [460*90 + \(\displaystyle \pi \) * 45²] cm²

Next you should convert the area to m².

What is the "total" area of the flower beds in m²?

 

[Laurenkiernan0507]

I was getting 4.14m2 for the area of one flower bed

so 40 flower beds 165.6m2

I ended up with 260ml for the 40 flower beds but it was incorrect

 

[tkhunny]

I was getting 4.14m2 for the area of one flower bed

That could be a problem. Please show your calculations - ALL intermediate results. What value did you uses for π?

 

[Laurenkiernan0507]

That could be a problem. Please show your calculations - ALL intermediate results. What value did you uses for π?

I think that's where I'm going wrong I didn't use pi.

I just done 460cm x 90cm then converted to metres

I think the number I would use for pi is 3.142? But would I add it or times it?

 

[Dr.Peterson]

I think that's where I'm going wrong I didn't use pi.

I just done 460cm x 90cm then converted to metres

I think the number I would use for pi is 3.142? But would I add it or times it?

The flower bed is not just a rectangle; it is a rectangle with semicircles at each end. So to find the area, you have to add the areas of a rectangle and a circle (two half-circles). What do you get for each part?

3.142 is not rounded appropriately; but you should use whatever you have been taught to use for pi. If you have not been told, just use the pi key on a calculator, which will be as accurate as the calculator can hold.

 

[JeffM]

I think that's where I'm going wrong I didn't use pi.

I just done 460cm x 90cm then converted to metres

I think the number I would use for pi is 3.142? But would I add it or times it?

Look again at the suggestion in post 2.

I might have stated it as

[MATH]40 * \left \{ (460 * 90) + \left ( \dfrac{1}{2} * \pi * \left \{ \dfrac{90}{2} \right \}^2 \right ) + \left ( \dfrac{1}{2} * \pi * \left \{ \dfrac{90}{2} \right \}^2 \right )\right \}.[/MATH]
Questions.

What am I multiplying by 40?

The expression inside the curled brackets contains three addends in parentheses?

What does each each addend represent?

Do you now see that you will indeed be adding terms where pi is a multiplicand?

And do see that what SK gave you is just a simplification of the expression above.

[MATH]40 * \left \{ (460 * 90) + \left ( \dfrac{1}{2} * \pi * \left \{ \dfrac{90}{2} \right \}^2 \right ) + \left ( \dfrac{1}{2} * \pi * \left \{ \dfrac{90}{2} \right \}^2 \right )\right \} =[/MATH]
[MATH]40 * \left \{ 460 * 90 + 2 * \left ( \dfrac{1}{2} * \pi 45^2 \right ) \right \} = 40 * (460 * 90 + \pi 45^2).[/MATH]