A little help with some cuboid measurments?

[matheus]

Hey guys,

I really struggle to get my head around these sorts of questions, often coming up with wildly erroneous answers, however if I see the correct answer and the logic of how it was obtained, I have found it is the best way for me to learn.

I really want to learn this stuff (high school dropout) and improve my math skills and hopefully one of you fine young mathematician's can assist me?

Pretty please

Keep up the great work guys!

 

[stapel]

I really struggle to get my head around these sorts of questions, often coming up with wildly erroneous answers, however if I see the correct answer and the logic of how it was obtained, I have found it is the best way for me to learn.

Okay. So what worked examples have you studied before attempting this?

i) They have provided you with a right triangle on the top of the cuboid, and have given you one leg and the hypotenuse. They have asked you for the other leg. Apply the appropriate Theorem.

ii) They have given you a triangle, ABC, with a height h = AB and a base b whose length you found in (i). They have asked you for the area A. Plug b and h into the formula for the area A = (1/2)bh. (And memorize this formula, if you haven't already.)

iii) They have given you a circle with a radius r. They have asked you for the area A of that circle. Plug the radius value into the formula for the area of a circle.

iv) This part is misleading, as the "total surface area" would include the sides of the cylindrical hole. But, from the way they've stated the question (in particular, in having you use "your answer to part (c)(iii)"), you are supposed to find only the area on the "outside". So find the areas of each of the individual sides, using the formula for the area of a rectangle. Then subtract the areas of the two circular cut-outs.

v) You have found the cross-sectional area of the cylinder in (iii). You know the height h from part (i). The volume of the cylinder in the product of the area and the height, so multiply.

vi) Find the volume of the cuboid. Subtract the volume of the cut-out.

If you get stuck, please reply showing your work for each part above. Thank you!

 

[matheus]

Mr Stapel,

I really can't thank you enough for your most helpful reply

I will now attempt the questions and report back how I get on.

Have a great day!