Answer:
The model swing should be 2.75 cm high.
Explanation:
Given:
A 168-cm tall person is 2 cm in Ming’s model.
If the actual swing is 231 cm high.
Now, to find how high should his model swing be.
Let the model swing be
![x\ cm.](https://img.qammunity.org/2020/formulas/mathematics/middle-school/5jlwgjcpl79bq0gb50khr9du8rq1jsrphx.png)
So, 168 cm tall person is equivalent to 2 cm.
Thus, 231 cm actual swing is equivalent to
model swing.
Now, we get the height of the swing in the model by using cross multiplication method:
![(168)/(2) =(231)/(x)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/34ecp305gc4qszrpe5tvgq2c9vrfkjgety.png)
By cross multiplication:
⇒
![168x=462](https://img.qammunity.org/2020/formulas/mathematics/middle-school/zeg1izdceao1mn32u8o6vpwc9nv01ojrnc.png)
Dividing both sides by 168 we get:
⇒
![x=2.75\ cm.](https://img.qammunity.org/2020/formulas/mathematics/middle-school/6hf8byqi9c35ygxdbjoy1zs5gluqlui2g0.png)
Therefore, the model swing should be 2.75 cm high.