Topic: Triangles
Time: 2 Hours
Answer all the questions.
Short Answer questions
- Prove that the line joining the midpoints of two of the sides of a triangle is parallel to the other side and half of it.
C
D
The diagonals of a quadrilateral ABCD intersect at a point O such that. Prove that ABCD is trapezium.- In the fig if AB || DC|| EF. Prove that.
F
E
If PE||RS, prove that D POE ~ DROS
S
EQQQQQ
Q
P
B
A
R
- A girl of height 120cm is walking past a lamp post at a speed of 1.5 meters per second finds the length of the shadow after 5 seconds to be 125cm. Find the height of the lamp post.
- S and T are points on sides PR and QR of DPQR such that ÐP = Ð RTS. Prove that D RPQ ~ DRTS.
- If DABC ~ DDEF and their areas are 196 cm2 and 225cm2 respectively. If FD = 22.5cm find CA
P
S
If the areas of two similar triangles are equal, prove that the triangles are congruent.O
A
B
Find ÐABP and ÐBAQ in the figure ifÐOPS = 35° and ÐSOB = 125°
- A ladder is placed against a wall such that its foot is at a distance of 3m from the wall to reach a height of 4m. Find the length of the ladder.
Big Questions
- State and prove Basic Proportionality theorem.
- Prove that the ratio between the medians, angle bisectors and altitudes are equal in two similar triangles.
- A triangle ABC is divided in two parts by drawing a line PQ parallel to the base BC. Find the ratio between AP and PB if the ratio between the area of triangles APQ and Trapezium PQCB is 1:2.
- D is the point on the side BC of a triangle ANC such that ÐADC = ÐBAC. Prove that CA2 = CB. CD.
- If the angle A of triangle ABC is bisected by AD prove that AB:AC = BD:DC.
- State and prove the Pythagoras theorem.
- BL and CM are the medians of a triangle ABC right angles at A. Prove that 4(BL2 + CM2) = 5 BC2.
- In an equilateral triangle ABC, D is the point on side BC such that BD= BC. Prove that 9AD2 = 7AB2.In any triangle ABC, AD is the median, AE is the altitude. Prove that AC2 = AD2 +BC. DE + Prove that the three times sum of the squares of the medians of a triangle is equal to four times the sum of the squares of their altitudes.
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