A triangle was dilated by a scale factor of 6. If [tex]\sin a ^{\circ}=\frac{4}{5}[/tex] and [tex]\overline{DE}[/tex] measures 30 units, how long is [tex]\overline{EF}[/tex]?

A. [tex]\overline{EF}=15.5[/tex] units
B. [tex]\overline{EF}=24[/tex] units
C. [tex]\overline{EF}=30[/tex] units
D. [tex]\overline{EF}=37.5[/tex] units



Answer :

Let's consider the given information and infer the solution step-by-step.

1. Understanding the Dilation:
- A triangle is dilated by a scale factor of 6. This means every side of the original triangle is multiplied by 6 to obtain the dilated triangle.

2. Given Measurements:
- After the dilation, the length of [tex]\(\overline{DE}\)[/tex] is measured to be 30 units.

3. Relationship Between Original and Dilated Lengths:
- If the given length [tex]\(\overline{DE}\)[/tex] is already 30 units after dilation, and the dilation factor is 6, then the original length of [tex]\(\overline{DE}\)[/tex] before dilation must have been:
[tex]\[ \text{Original Length of } \overline{DE} = \frac{30 \text{ units}}{6} = 5 \text{ units} \][/tex]

4. Calculating [tex]\(\overline{EF}\)[/tex] after Dilation:
- However, the length given as 30 units is after the dilation. Since the same dilation factor applies equally to all parts of the triangle proportionally, the corresponding original length for [tex]\(\overline{EF}\)[/tex] before dilation should have been:
[tex]\[ \text{Original Length of } \overline{EF} = \frac{\text{Length of } \overline{DE}}{\text{Scale Factor}} \][/tex]
But since [tex]\(\overline{DE}\)[/tex] and [tex]\(\overline{EF}\)[/tex] are part of the corresponding sides in similar triangles, their dilated lengths remain proportional.

5. Final Confirmation:
- Given the choices, the length of [tex]\(\overline{EF}\)[/tex] after applying the same scale factor would end up being:
[tex]\[ \text{Length of } \overline{EF} = 30 \text{ units} \][/tex]

Thus, the length of [tex]\(\overline{EF}\)[/tex] should be:
[tex]\[ \boxed{30 \text{ units}} \][/tex]