In $ \Delta \mathrm{PQR}, \mathrm{M} $ and $ \mathrm{N} $ are the midpoints of $ \mathrm{PQ} $ and PR respectively. If the area of $ \triangle \mathrm{PMN} $ is $ 24 \mathrm{~cm}^{2} $, find the area of $ \triangle \mathrm{PQR} $.
Given:
In \( \Delta \mathrm{PQR}, \mathrm{M} \) and \( \mathrm{N} \) are the midpoints of \( \mathrm{PQ} \) and PR respectively.
The area of \( \triangle \mathrm{PMN} \) is \( 24 \mathrm{~cm}^{2} \).
To do:
We have to find the area of \( \triangle \mathrm{PQR} \).
Solution:
We know that,
Area of the triangle formed by joining the midpoints of the sides of a triangle is equal to one-fourth the area of the given triangle.
Similarly,
Area of the triangle formed by a vertex and the midpoints of the adjacent sides is equal to one-fourth the area of the given triangle.
Therefore,
Area of triangle PMN $=\frac{1}{4}\times$ Area of triangle PQR
$\Rightarrow 24=\frac{1}{4}\times$ Area of triangle PQR
Area of triangle PQR $=24\times4=96\ cm^2$
The area of \( \triangle \mathrm{PQR} \) is $96\ cm^2$.
Related Articles In \( \triangle \mathrm{ABC}, \mathrm{M} \) and \( \mathrm{N} \) are the midpoints of \( \mathrm{AB} \) and \( \mathrm{AC} \) respectively. If the area of \( \triangle \mathrm{ABC} \) is \( 90 \mathrm{~cm}^{2} \), find the area of \( \triangle \mathrm{AMN} \).
\( \mathrm{X}, \mathrm{Y} \) and \( \mathrm{Z} \) are the midpoints of the sides of \( \Delta \mathrm{PQR} . \mathrm{A}, \mathrm{B} \) and \( \mathrm{C} \) are the midpoints of the sides of \( \triangle \mathrm{XYZ} \). If \( \mathrm{PQR}=240 \mathrm{~cm}^{2} \), find \( \mathrm{XYZ} \) and \( \mathrm{ABC} \).
\( \triangle \mathrm{PQR} \sim \triangle \mathrm{ZYX} . \quad \) If \( \mathrm{PQ}: \mathrm{ZY}=5: 3 \) and \( \mathrm{PR}=10 \mathrm{~cm} \), find \( \mathrm{ZX} \).
\( \triangle \mathrm{ABC} \sim \triangle \mathrm{PQR} . \quad \) If \( \quad \mathrm{AB}+\mathrm{BC}=12 \mathrm{~cm} \) \( \mathrm{PQ}+\mathrm{QR}=15 \mathrm{~cm} \) and \( \mathrm{AC}=8 \mathrm{~cm} \), find \( \mathrm{PR} \).
Choose the correct answer from the given four options:If in two triangles \( \mathrm{ABC} \) and \( \mathrm{PQR}, \frac{\mathrm{AB}}{\mathrm{QR}}=\frac{\mathrm{BC}}{\mathrm{PR}}=\frac{\mathrm{CA}}{\mathrm{PQ}} \), then(A) \( \triangle \mathrm{PQR} \sim \triangle \mathrm{CAB} \)(B) \( \triangle \mathrm{PQR} \sim \triangle \mathrm{ABC} \)(C) \( \triangle \mathrm{CBA} \sim \triangle \mathrm{PQR} \)(D) \( \triangle \mathrm{BCA} \sim \triangle \mathrm{PQR} \)
Construct a triangle \( \mathrm{PQR} \) in which \( \mathrm{QR}=6 \mathrm{~cm}, \angle \mathrm{Q}=60^{\circ} \) and \( \mathrm{PR}-\mathrm{PQ}=2 \mathrm{~cm} \).
In \( \triangle \mathrm{PQR}, \quad \angle \mathrm{P}=\angle \mathrm{Q}+\angle \mathrm{R}, \mathrm{PQ}=7 \) and \( \mathrm{QR}=25 \). Find the perimeter of \( \triangle \mathrm{PQR} \).
Two sides \( \mathrm{AB} \) and \( \mathrm{BC} \) and median \( \mathrm{AM} \) of one triangle \( \mathrm{ABC} \) are respectively equal to sides \( \mathrm{PQ} \) and \( \mathrm{QR} \) and median \( \mathrm{PN} \) of \( \triangle \mathrm{PQR} \) (see Fig. 7.40). Show that:(i) \( \triangle \mathrm{ABM} \equiv \triangle \mathrm{PQN} \)(ii) \( \triangle \mathrm{ABC} \cong \triangle \mathrm{PQR} \)"\n
In a \( \Delta \mathrm{PQR}, \mathrm{PR}^{2}-\mathrm{PQ}^{2}=\mathrm{QR}^{2} \) and \( \mathrm{M} \) is a point on side \( \mathrm{PR} \) such that \( \mathrm{QM} \perp \mathrm{PR} \).Prove that \( \mathrm{QM}^{2}=\mathrm{PM} \times \mathrm{MR} \).
Name the types of following triangles:(a) Triangle with lengths of sides \( 7 \mathrm{~cm}, 8 \mathrm{~cm} \) and \( 9 \mathrm{~cm} \).(b) \( \triangle \mathrm{ABC} \) with \( \mathrm{AB}=8.7 \mathrm{~cm}, \mathrm{AC}=7 \mathrm{~cm} \) and \( \mathrm{BC}=6 \mathrm{~cm} \).(c) \( \triangle \mathrm{PQR} \) such that \( \mathrm{PQ}=\mathrm{QR}=\mathrm{PR}=5 \mathrm{~cm} \).(d) \( \triangle \mathrm{DEF} \) with \( \mathrm{m} \angle \mathrm{D}=90^{\circ} \)(e) \( \triangle \mathrm{XYZ} \) with \( \mathrm{m} \angle \mathrm{Y}=90^{\circ} \) and \( \mathrm{XY}=\mathrm{YZ} \).(f) \( \Delta \mathrm{LMN} \) with \( \mathrm{m} \angle \mathrm{L}=30^{\circ}, \mathrm{m} \angle \mathrm{M}=70^{\circ} \) and \( \mathrm{m} \angle \mathrm{N}=80^{\circ} \).
10. Construct \( \triangle \mathrm{PQR} \) with \( \mathrm{PQ}=4.5 \mathrm{~cm}, \angle \mathrm{P}=60^{\circ} \) and \( \mathrm{PR}=4.5 \mathrm{~cm} . \) Measure \( \angle \mathrm{Q} \) and \( \angle \mathrm{R} \). What type of a triangle is it?
\( \Delta \mathrm{ABC} \sim \Delta \mathrm{XZY} \). If the perimeter of \( \triangle \mathrm{ABC} \) is \( 45 \mathrm{~cm} \), the perimeter of \( \triangle \mathrm{XYZ} \) is \( 30 \mathrm{~cm} \) and \( \mathrm{AB}=21 \mathrm{~cm} \), find \( \mathrm{XY} \).
\( A, B \) and \( C \) are the midpoints of the sides of \( \Delta X Y Z \). \( P, Q \) and \( R \) are the midpoints of the sides of \( \triangle \mathrm{ABC} \). If \( \mathrm{ABC}=24 \mathrm{~cm}^{2} \), find $XYZ$ and $PQR$.
If \( \Delta \mathrm{ABC} \sim \Delta \mathrm{DEF}, \mathrm{AB}=4 \mathrm{~cm}, \mathrm{DE}=6 \mathrm{~cm}, \mathrm{EF}=9 \mathrm{~cm} \) and \( \mathrm{FD}=12 \mathrm{~cm} \), find the perimeter of \( \triangle \mathrm{ABC} \).
\( \triangle \mathrm{ABC} \sim \triangle \mathrm{ZYX} . \) If \( \mathrm{AB}=3 \mathrm{~cm}, \quad \mathrm{BC}=5 \mathrm{~cm} \), \( \mathrm{CA}=6 \mathrm{~cm} \) and \( \mathrm{XY}=6 \mathrm{~cm} \), find the perimeter of \( \Delta \mathrm{XYZ} \).
Kickstart Your Career
Get certified by completing the course
Get Started