$ \mathrm{AC} $ and $ \mathrm{BD} $ are chords of a circle which bisect each other. Prove that (i) $ \mathrm{AC} $ and $ \mathrm{BD} $ are diameters, (ii) $ \mathrm{ABCD} $ is a rectangle.
Given:
\( \mathrm{AC} \) and \( \mathrm{BD} \) are chords of a circle which bisect each other.
To do:
We have to prove that
(i) \( \mathrm{AC} \) and \( \mathrm{BD} \) are diameters
(ii) \( \mathrm{ABCD} \) is a rectangle.
Solution:
(i) Let $AC$ and $BD$ be two chords of a circle which bisect each other at $P$.
In $\triangle AOB$ and $\triangle COD$,
$OA = OC$ ($O$ is the mid-point of $AC$)
$\angle AOB = \angle COD$ (Vertically opposite angles)
$OB = OD$ ($O$ is the mid-point of $BD$)
Therefore, by SAS congruency,
$\triangle CPD \cong \triangle APB$
This implies,
$\overparen{C D}=\overparen{A B}$.........(i) (CPCT)
Similarly,
In $\triangle A P D$ and $\triangle C P B$, we get,
$\overparen{C B}=\overparen{A D}$.........(ii) (CPCT)
Adding (i) and (ii), we get,
$\overparen{C D}+\overparen{C B}=\overparen{A B}+\overparen{A D}$
$\overparen{B C D}=\overparen{B A D}$
Therefore,
$BD$ divides the circle into two equal parts.
This implies,
$BD$ is a diameter.
Similarly,
$AC$ is a diameter.
(ii) $AC$ and $BD$ bisect each other.
This implies,
$ABCD$ is a parallelogram and
$AC = BD$
Therefore,
$ABCD$ is a rectangle.
Hence proved.
Related Articles
- Diagonals \( \mathrm{AC} \) and \( \mathrm{BD} \) of a trapezium \( \mathrm{ABCD} \) with \( \mathrm{AB} \| \mathrm{DC} \) intersect each other at \( \mathrm{O} \). Prove that ar \( (\mathrm{AOD})=\operatorname{ar}(\mathrm{BOC}) \).
- In rhombus \( \mathrm{ABCD}, \mathrm{AC}=16 \) and \( \mathrm{BD}=30 \). Find the perimeter of rhombus \( \mathrm{ABCD} \).
- \( \mathrm{ABCD} \) is a rectangle in which diagonal \( \mathrm{AC} \) bisects \( \angle \mathrm{A} \) as well as \( \angle \mathrm{C} \). Show that:(i) \( \mathrm{ABCD} \) is a square (ii) diagonal \( \mathrm{BD} \) bisects \( \angle \mathrm{B} \) as well as \( \angle \mathrm{D} \).
- Diagonals \( \mathrm{AC} \) and \( \mathrm{BD} \) of a quadrilateral \( \mathrm{ABCD} \) intersect each other at \( \mathrm{P} \). Show that ar \( (\mathrm{APB}) \times \operatorname{ar}(\mathrm{CPD})=\operatorname{ar}(\mathrm{APD}) \times \operatorname{ar}(\mathrm{BPC}) \).[Hint: From \( \mathrm{A} \) and \( \mathrm{C} \), draw perpendiculars to \( \mathrm{BD} \).]
- The perimeter of rhombus \( \mathrm{ABCD} \) is \( 116 . \) If \( \mathrm{AC}=42 \), find \( \mathrm{BD} \).
- In a quadrilateral \( \mathrm{ABCD}, \angle \mathrm{A}+\angle \mathrm{D}=90^{\circ} \). Prove that \( \mathrm{AC}^{2}+\mathrm{BD}^{2}=\mathrm{AD}^{2}+\mathrm{BC}^{2} \) [Hint: Produce \( \mathrm{AB} \) and DC to meet at E]
- In figure below, \( l \| \mathrm{m} \) and line segments \( \mathrm{AB}, \mathrm{CD} \) and \( \mathrm{EF} \) are concurrent at point \( \mathrm{P} \).Prove that \( \frac{\mathrm{AE}}{\mathrm{BF}}=\frac{\mathrm{AC}}{\mathrm{BD}}=\frac{\mathrm{CE}}{\mathrm{FD}} \)."
- Diagonals \( \mathrm{AC} \) and \( \mathrm{BD} \) of a quadrilateral \( A B C D \) intersect at \( O \) in such a way that ar \( (\mathrm{AOD})=\operatorname{ar}(\mathrm{BOC}) \). Prove that \( \mathrm{ABCD} \) is a trapezium.
- \( \mathrm{O} \) is the point of intersection of the diagonals \( \mathrm{AC} \) and \( \mathrm{BD} \) of a trapezium \( \mathrm{ABCD} \) with \( \mathrm{AB} \| \mathrm{DC} \). Through \( \mathrm{O} \), a line segment \( \mathrm{PQ} \) is drawn parallel to \( \mathrm{AB} \) meeting \( \mathrm{AD} \) in \( \mathrm{P} \) and \( \mathrm{BC} \) in \( \mathrm{Q} \). Prove that \( \mathrm{PO}=\mathrm{QO} \).
- \( \mathrm{ABCD} \) is a rhombus. Show that diagonal \( \mathrm{AC} \) bisects \( \angle \mathrm{A} \) as well as \( \angle \mathrm{C} \) and diagonal \( \mathrm{BD} \) bisects \( \angle \mathrm{B} \) as well as \( \angle \mathrm{D} \).
- In figure below, if \( \angle \mathrm{ACB}=\angle \mathrm{CDA}, \mathrm{AC}=8 \mathrm{~cm} \) and \( \mathrm{AD}=3 \mathrm{~cm} \), find \( \mathrm{BD} \)."
Kickstart Your Career
Get certified by completing the course
Get Started
To Continue Learning Please Login
Login with Google