I'm still not quite sure about answers to the 4 mark cheese question. Four markers are usually trickier than they look, and although this DID look tricky, the answers posted up seem a bit too simplistic to me. When I first looked at the question, I got those answers, but after thinking about it for a bit, it didn't look right to me.
Length – Circumference of a sector multiplied by 4.
40/360 x 2 x П x 15 x 4 = 41.9cm (to 1 dec. Place)
Depth – Depth of the sector multiplied by 3.
7x 3 = 21cm
Height – For a 4 mark question, I don’t think height of the box is not merely the radius of the sector shown. I reckon it’s far too simple to be that. How can the height of the box be 15cm if the radius is slopping up? This is my working out.
Circumference of the sector divided by 2 (to break the sector into a right angle triangle(ignoring its curve))
40/360 x 2 x П x 15 = 41.889...
41.889/2 = 5.235987..
Now use the radius of the sector (15) and Pythagoras’ theorem to work out the height of the sector.
15^2 – 5.235987^2... = 197.5845...
Square root of 197.5845 = 14.1 cm (to 1 dec. place)
That's what I got...I don't know if it's right though