Advertisements
Advertisements
प्रश्न
In the below fig. ∠AOB = 90°, AC = BC, OA = 12 cm and OC = 6.5 cm. Find the area of
ΔAOB.
Advertisements
उत्तर
Since, the midpoint of the hypotenuse of a right triangle is equidistant from the vertices
∴ CA = CB = OC
⇒ AB = 13 = 6.5cm
In a right angle triangle OAB, we have
AB2 = OB2 + OA2
⇒ 132 = OB2 + 122
⇒ OB2 = 132 - 122 = 169 - 144 = 25
⇒ OB = 5
∵ ar (ΔAOB) = `1/2` (OA×OB) = `1/2` (12 ×5 ) = 30cm2
APPEARS IN
संबंधित प्रश्न
A point D is taken on the side BC of a ΔABC such that BD = 2DC. Prove that ar(Δ ABD) =
2ar (ΔADC).
ABCD is a parallelogram whose diagonals AC and BD intersect at O. A line through O
intersects AB at P and DC at Q. Prove that ar (Δ POA) = ar (Δ QOC).
The area of the figure formed by joining the mid-points of the adjacent sides of a rhombus with diagonals 16 cm and 12 cm is
ABCD is a trapezium with parallel sides AB =a and DC = b. If E and F are mid-points of non-parallel sides AD and BC respectively, then the ratio of areas of quadrilaterals ABFEand EFCD is
Find the area of a rectangle whose length and breadth are 25 m and 16 cm.
Cheggu’s wife asked him to make a circle with the wire. She knew it had an area of 800 square meters.
- Why did Cheggu not choose a rectangle? Explain.
Each line gives a story. You have to choose the question which makes the best story problem. The first one is already marked.
- 352 children from a school went on a camping trip. Each tent had a group of 4 children.
a) How many children did each tent have? b) How many tents do they need? c) How many children in all are in the school?
Area of a rectangle with length 5 cm and breadth 3 cm is ______.
Find all the possible dimensions (in natural numbers) of a rectangle with a perimeter 36 cm and find their areas.
Find the area of the following figure by counting squares:
