Question

Find the surface area of the following composite figure. 12 ft 32 ft 10 ft 10 ft A. 1480 sq. feet B. 1620 sq. feet C. 1720 sq. feet D. 1820 sq feet

Answer 1

prism area

$\begin{gathered} SA=2lw+2lh+2wh \\ SA=2(10\times10)+2(10\times32)+2(10\times32) \\ SA=2(100)+2(320)+2(320) \\ SA=200+640+640 \\ SA=1480 \end{gathered}$

then, pyramid area

$\begin{gathered} SA=l(2\times ap+l) \\ SA=10(2\times12+10) \\ SA=10(24+10) \\ SA=10(34) \\ SA=340 \end{gathered}$

therfore, area of the figure

$SA=1480+340=1820$

answer: D. 1820 sq feet