Latih Diri 3.1d – Buku Teks Matematik Tingkatan 1 (KSSM) – Kuasa Dua & Punca Kuasa Dua

Soalan 1:
Cari nilai bagi setiap yang berikut tanpa menggunakan kalkulator.
(a) √81
(b) √49
(c) √121
(d) √900
(e) √49/84
(f) √7 1/9
(g) √50/128
(h) √2.25


Penyelesaian:
(a)
$$ \begin{aligned} \sqrt{81} & =\sqrt{9 \times 9} \\ & =9 \end{aligned} $$
(b)
$$ \begin{aligned} \sqrt{49} & =\sqrt{7 \times 7} \\ & =7 \end{aligned} $$
(c)
$$ \begin{aligned} \sqrt{121} & =\sqrt{11 \times 11} \\ & =11 \end{aligned} $$
(d)
$$ \begin{aligned} \sqrt{900} & =\sqrt{30 \times 30} \\ & =30 \end{aligned} $$
(e)
$$ \begin{aligned} \sqrt{\frac{49}{81}} & =\sqrt{\frac{7}{9} \times \frac{7}{9}} \\ & =\sqrt{\left(\frac{7}{9}\right)^2} \\ & =\frac{7}{9} \end{aligned} $$


(f)
$$ \begin{aligned} \sqrt{7 \frac{1}{9}} & =\sqrt{\frac{64}{9}} \\ & =\sqrt{\left(\frac{8}{3}\right)^2} \\ & =\frac{8}{3} \\ & =2 \frac{2}{3} \end{aligned} $$
(g)
$$ \begin{aligned} \sqrt{\frac{50}{128}} & =\sqrt{\frac{25}{64}} \\ & =\sqrt{\left(\frac{5}{8}\right)^2} \\ & =\frac{5}{8} \end{aligned} $$


(h)
$$ \begin{aligned} \sqrt{2.25} & =\sqrt{2 \frac{25}{100}} \\ & =\sqrt{2 \frac{1}{4}} \\ & =\sqrt{\frac{9}{4}} \\ & =\sqrt{\left(\frac{3}{2}\right)^2} \\ & =\frac{3}{2} \\ & =1.5 \end{aligned} $$