Question

If $(8x{)}^2+(6x{)}^2=d^2$ and $d=200$, then $8x\times 6x$ is equal to

• A. 18,200
• B. 18,500
• C. 18,900
• D. 19,200

Answer 1

Answer: (D)

19,200

$(8x{)}^2+(6x{)}^2=d^2$
or $64x^2+36x^2=d^2$
or $100x^2=d^2$
or $d=\sqrt{100x^2}=10x$
$10x=200$
$\therefore x=\frac{200}{10}=20$
Hence, $8x\times 6x=8\times 20\times 6\times 20=19,200$