Find the surface area of the water in the given prism

[chwala]

Homework Statement

See attached ( past paper question)

Relevant Equations

Knowledge of prisms

My query in only on the highlighted part...c.ii.

Find the question below;

Find the markscheme here

part c(ii) does not seem correct as i have;
$A_1=0.5 ×(0.65+0.84)0.3 ×2=0.447m^2$
$A_2 = 0.65 ×1.6=1.04m^2$
$A_3 = (0.3146 × 1.6)2=1.00672m^2$
Total surface area = $A_1+A_2+A_3=0.447+1.04+1.00672=2.494m^2$...

For part c.(i), i was able to use similarity (i used a right angle triangle from the cross-section) to show that,
i.e $\dfrac {0.477}{0.15}$=$\dfrac {0.3}{x}$
$x=0.094$ therefore, $w = 0.65+2(0.094)=0.8386≈0.84$ to 3 2 significant figures.

 

[chwala]

aaargh! its the english man, i figured it out, $0.84 × 1.6!$ Area of surface and not Surface area! phew

 

[BvU]

$x=0.094$ therefore, $w = 0.65+2(0.094)=0.8386≈0.84$ to 3 significant figures.

0.8386 to 3 significant figures amounts to 0.839

(i.e. a leading zero does not count as a significant figure)

$\$

 

[chwala]

0.8386 to 3 significant figures amounts to 0.839

(i.e. a leading zero does not count as a significant figure)

$\$

...to two significant figures...yeah, i know that. cheers bvu...