Respuesta :

Answer:

B

Step-by-step explanation:

The figure consists of an inner rectangle with dimensions 8 by 10 and a right triangle on the bottom right with dimensions

base = 12 - 8 = 4 cm and height = 10 - 5 = 5 cm

Total area (A) is equal to the sum of the area of the rectangle and the right triangle, that is

area of rectangle = 10 × 8 = 80 cm²

area of triangle = 0.5 × 4 × 5 = 10 cm²

Hence

A = 80 cm² + 10 cm² = 90 cm² → B

The area of the composite figure which is a combination of a rectangle and triangle is 90cm².

Option B) 90cm² is the correct answer.

What is a rectangle and a triangle?

A rectangle is a 2-dimensional shape with parallel opposite sides equal to each other and four angles are right angles.

The area of a rectangle is expressed;

A = l × b

Where l is dimension of length and b is dimension of breadth.

A triangle is a 3-sided polygon with three edges and three vertices.

A right angled triangle is a triangle with one of the angles as 90 degrees.

The area of a right angled triangle is expressed as;

A = (1/2)ab

Where a and b are the length of the two sides other than the hypotenuse

The figure in the image is a combination of a rectangle and a triangle.

For the rectangle

  • Dimension of length l = 10cm
  • Dimension of breadth b = 8cm

Hence,

Area = l × b

Area = 10cm × 8cm

Area of Rectangle = 80cm²

For the right angled triangle

  • Diamention of a = 10cm - 5cm = 5cm
  • Diamention of b = 12cm - 8cm = 4cm

Hence,

Area = (1/2)ab

Area = (1/2) × 5cm × 4cm  

Area of right angled triangle = 10cm²

Now, area of the the figure will be;

A = Area of Rectangle + Area of right angled triangle

A = 80cm² + 10cm²

A = 90cm²

The area of the composite figure which is a combination of a rectangle and triangle is 90cm².

Option B) 90cm² is the correct answer.

Learn more about area of triangles here: brainly.com/question/19305981

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