Answer: C

Explanation:

Area of a triangle = ½ * base * height
So, the area = ½* 5 * 10
                   =25 square meters

Answer: D

Explanation:

The area of a right angled triangle = ½ * base * height

Base = 10, Hypotenuse = 20
Height² = Hypotenuse² – Base²
                   = 20² – 16²
                   = 400 – 256
      Height² = 144
      Height = 12

Area = ½ * base * height

               = ½ * 10 * 12
               = 60 meters

Answer: A

Explanation:

Let the sides are 10x, 24x, and 26x.
The perimeter is 300 m.
So, 10x + 24x + 26x = 300
60x = 300
x= 5

So, the sides are 10 *5 = 50 meters
24 * 5 = 100 meters
26 * 5 = 130 meters
10² + 24² = 26² so, it is a right triangle.
       100 + 576 = 676

The area of a right triangle is = 1/2 * base * height
              = 1/2 * 50 * 100
              = 2500 m²

Answer: A

Explanation:

One round of the park is equal to the perimeter of the park.

So, by completing one round, the cat covers a distance equal to the perimeter of the park.

Now, Distance or perimeter = speed * time
                                            = 18 * (10/60)
                                            = 3 km or 3000 meters

Let Length = 4x and breadth = 2x

So, Perimeter: 2 (4x + 2x) = 3000
8x + 4x = 3000
12x = 3000
x= 3000/12= 250 meters

So, Length = 4 * 250 = 1000 meters

And, Breadth = 2 * 250 = 500 meters

Area = Length * Breadth
      = 1000 * 500
      = 50000 sq. m.

Answer: C

Explanation:

Let the length of the rectangle be 5x, and breadth be 3x,
Perimeter of a rectangle = 2(l +b) = 480
                                         2(5x + 3x) = 480
                                         2 x 8x = 480
                                         16x = 480
                                         x = 480/16 = 30

∴ Length = 5 x 30 = 150 m
                  Breadth = 3 x 30 = 90 m

And, Area of rectangle = L x B
                                     = 150 x 90 = 13500 m²