मराठी

ABC and BDE are two equilateral triangles such that D is the mid-point of BC. Then ar (BDE) = 14 ar (ABC).

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प्रश्न

ABC and BDE are two equilateral triangles such that D is the mid-point of BC. Then ar (BDE) = `1/4` ar (ABC).

पर्याय

  • True

  • False

MCQ
चूक किंवा बरोबर
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उत्तर

This statement is True.

Explanation:

Given: ΔABC and ΔBDE are two equilateral triangles.

Suppose that each sides of triangle ABC be x.

Similarly, D is the mid-point of BC.

So, each side of triangle BDE is `x/2`.

Now, `(Area(ΔBDE))/(Area(ΔABC)) = (sqrt(3)/4 xx (x/2)^2)/(sqrt(3) / 4 xx x^2)`

= `x^2/(4x^2)`

= `1/4`

Therefore, area (ΔBDE) = `1/4` area (ΔABC).

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  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
पाठ 9: Areas of Parallelograms & Triangles - Exercise 9.2 [पृष्ठ ८८]

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एनसीईआरटी एक्झांप्लर Mathematics Exemplar [English] Class 9
पाठ 9 Areas of Parallelograms & Triangles
Exercise 9.2 | Q 4. | पृष्ठ ८८

व्हिडिओ ट्यूटोरियलVIEW ALL [1]

संबंधित प्रश्‍न

In a triangle ABC, E is the mid-point of median AD. Show that ar (BED) = 1/4ar (ABC).


In the given figure, ABC and ABD are two triangles on the same base AB. If line-segment CD is bisected by AB at O, show that ar (ABC) = ar (ABD).


In the given figure, diagonals AC and BD of quadrilateral ABCD intersect at O such that OB = OD. If AB = CD, then show that:

(i) ar (DOC) = ar (AOB)

(ii) ar (DCB) = ar (ACB)

(iii) DA || CB or ABCD is a parallelogram.

[Hint: From D and B, draw perpendiculars to AC.]


D and E are points on sides AB and AC respectively of ΔABC such that

ar (DBC) = ar (EBC). Prove that DE || BC.


In the given figure, ABCDE is a pentagon. A line through B parallel to AC meets DC produced at F. Show that

(i) ar (ACB) = ar (ACF)

(ii) ar (AEDF) = ar (ABCDE)


In the given figure, AP || BQ || CR. Prove that ar (AQC) = ar (PBR).


In the following figure, ABC and BDE are two equilateral triangles such that D is the mid-point of BC. If AE intersects BC at F, show that

(i) ar (BDE) = 1/4 ar (ABC)

(ii) ar (BDE) = 1/2 ar (BAE)

(iii) ar (ABC) = 2 ar (BEC)

(iv) ar (BFE) = ar (AFD)

(v) ar (BFE) = 2 ar (FED)

(vi) ar (FED) = 1/8 ar (AFC)

[Hint : Join EC and AD. Show that BE || AC and DE || AB, etc.]


A point E is taken on the side BC of a parallelogram ABCD. AE and DC are produced to meet at F. Prove that ar (ADF) = ar (ABFC)


If the medians of a ∆ABC intersect at G, show that ar (AGB) = ar (AGC) = ar (BGC) = `1/3` ar (ABC)


In the following figure, X and Y are the mid-points of AC and AB respectively, QP || BC and CYQ and BXP are straight lines. Prove that ar (ABP) = ar (ACQ).


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