$ \begin{aligned}16.\quad&\textrm{Diberikan pernyataan-pernyataan berikut}\\ &(i)\quad \pi(2r)\qquad\qquad\qquad (iii)\quad \displaystyle \frac{1}{2}\pi d\\ &(ii)\quad \pi.r^{\displaystyle 2}\qquad\qquad\qquad (iv)\quad \displaystyle \frac{1}{4}\pi d^{\displaystyle 2}\\&\textrm{jika r jari-jari lingkaran dan d adalah diameternya}\\&\textrm{Pernyataan di atas yang merupakan formula luas }\\ &\textrm{lingkaran adalah}\:....\\ &\text{a}.\quad (i)\quad \textrm{dan}\quad (ii)\\ &\text{b}.\quad (i)\quad \textrm{dan}\quad (iv)\\ &\text{c}.\quad (ii)\quad \textrm{dan}\quad (iii)\\ &\text{d}.\quad (ii)\quad \textrm{dan}\quad (iv)\\\\ &\textrm{Jawab}:\quad \textbf{d}\\ &\textrm{Cukup jelas}\end{aligned}$.
$ \begin{aligned}17.\quad&\textrm{Luas lingkaran yang berjari-jari}\quad 7\:\: \textrm{cm adalah}=\:....\\ &\text{a}.\quad 44\quad \textrm{cm}^{\displaystyle 2}\\ &\text{b}.\quad 88\quad \textrm{cm}^{\displaystyle 2}\\ &\text{c}.\quad 154\quad \textrm{cm}^{\displaystyle 2}\\ &\text{d}.\quad 308\quad \textrm{cm}^{\displaystyle 2}\\\\ &\textrm{Jawab}:\quad \textbf{c}\\ &L=\pi r^{\displaystyle 2}=\displaystyle \frac{22}{7}.7^{\displaystyle 2}=154\:\: \textrm{cm}^{\displaystyle 2}\end{aligned}$.
$ \begin{aligned}18.\quad&\textrm{Luas lingkaran yang bediameter}\quad 20\:\: \textrm{cm adalah}=\:....\\ &\text{a}.\quad 12,56\quad \textrm{cm}^{\displaystyle 2}\\ &\text{b}.\quad 314\quad \textrm{cm}^{\displaystyle 2}\\ &\text{c}.\quad 62,8\quad \textrm{cm}^{\displaystyle 2}\\ &\text{d}.\quad 31,4\quad \textrm{cm}^{\displaystyle 2}\\\\ &\textrm{Jawab}:\quad \textbf{b}\\ &L=\displaystyle \frac{1}{4}\pi d^{\displaystyle 2}=\displaystyle \frac{1}{4}.(3,14).20^{\displaystyle 2}=314\:\: \textrm{cm}^{\displaystyle 2}\end{aligned}$.
$ \begin{aligned}19.\quad&\textrm{Jari-jari lingkaran dengan luasnya}\quad 36\pi\:\: cm^{\displaystyle 2}\:\textrm{adalah}=\:....\\ &\text{a}.\quad 6\quad \textrm{cm}\\ &\text{b}.\quad 9\quad \textrm{cm}\\ &\text{c}.\quad 12\quad \textrm{cm}\\ &\text{d}.\quad 6\pi\quad \textrm{cm}\\\\ &\textrm{Jawab}:\quad \textbf{a}\\ &L=\pi r^{\displaystyle 2}\Leftrightarrow 36\pi=\pi r^{\displaystyle 2}\Leftrightarrow r=\sqrt{36}=6\:\: \textrm{cm}\end{aligned}$.
$ \begin{aligned}20.\quad&\textrm{Dua lingkaran dengan jari-jari masing-masing}\\ &8\:\:\textrm{cm dan 10 cm. Perbandingan luas untuk}\\ &\textrm{kedua lingkaran tersebut adalah}=\:....\\ &\text{a}.\quad 4:5\\ &\text{b}.\quad 8:25\\ &\text{c}.\quad 16:25\\ &\text{d}.\quad 16:125\\\\ &\textrm{Jawab}:\quad \textbf{c}\\ &\displaystyle \frac{L_{\displaystyle 8}}{L_{\displaystyle 10}}=\displaystyle \frac{\pi.8^{\displaystyle 2}}{\pi.10^{\displaystyle 2}}=\frac{16}{25}\end{aligned}$.
Tidak ada komentar:
Posting Komentar
Informasi