Triangle DEF (not shown) is similar to ABC shown, with angle B congruent to angle E and angle C congruent to angle F. The length of side DE is 6 cm. If the area of ABC is 5 square centimeters, what is the area of DEF ?

Respuesta :

Answer:

Area of ΔDEF is [tex]45\ cm^2[/tex].

Step-by-step explanation:

Given;

ΔABC and  ΔDEF is similar and ∠B ≅ ∠E.

Length of AB = [tex]2\ cm[/tex] and

Length of DE = [tex]6\ cm[/tex]

Area of ΔABC = [tex]5\ cm^2[/tex]

Solution,

Since, ΔABC and  ΔDEF is similar and ∠B ≅ ∠E.

Therefore,

[tex]\frac{Area\ of\ triangle\ 1}{Area\ of\ triangle\ 2} =\frac{AB^2}{DE^2}[/tex]

Where triangle 1 and triangle 2 is  ΔABC and  ΔDEF respectively.

If two triangles are similar, then the ratio of the area of both triangles is proportional to the square of the ratio of their corresponding sides.

[tex]\frac{5}{Area\ of\ triangle\ 2} =\frac{2^2}{6^2}\\ \frac{5}{Area\ of\ triangle\ 2}=\frac{4}{36}\\ Area\ of\ triangle\ 2=\frac{5\times36}{4} =5\times9=45\ cm^2[/tex]

Thus the area of  ΔDEF is [tex]45\ cm^2[/tex].