Question

In $△DEF$ &$△PQR$, $\angle R=\angle F$, then both triangles are similar if

• A. $\frac{DF}{PR}=\frac{FE}{RQ}$
• B. $\frac{DE}{PQ}=\frac{DF}{PR}$
• C. $\frac{DE}{PR}=\frac{DF}{RQ}$
• D. $\frac{DE}{QR}=\frac{EF}{PR}$

Answer 1

The correct option is A $\frac{DF}{PR}=\frac{FE}{RQ}$

In$△DEF$ and $△PQR$

if $\angle R=\angle F$

then the ratios of the sides including these angles must be equal.

So, that SAS criteria of similarity can be applied.

i.e $\frac{DF}{PR}=\frac{FE}{RQ}$