Question

4. Find the area of an isosceles right triangle whose equal sides are 15 cm each.











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Answer 1

Given :

• Side of an isosceles triangle = 15 cm

To find :

• Area of isosceles triangle

According to the question,

➞ Area of isosceles triangle = ½ × base × height

➞ Area of isosceles triangle = ½ × 15 cm × 15 cm

➞ Area of isosceles triangle = 7.5 cm × 15 cm

➞ Area of isosceles triangle = 112.5 cm²

• So, the area of isosceles triangle is 112.5 cm².

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★ More formulas :

• Area of rectangle = Length × Breadth
• Area of square = Side × Side
• Surface area of a cube = 6a²
• Surface area of cuboid = 2(lb + bh + hl)
• Volume of cuboid = l × b × h
• Total surface area of a hemisphere = 3πr²
• Curved surface area of a cone = πrl
• Total surface area of a cylinder = 2πr(r + h)
• Perimeter of rectangle = 2(Length + Breadth)
• Perimeter of triangle = Sum of all its side
• Perimeter of square = 4a

Answer 2

Answer:

Given :-

• An isosceles right triangle whose equal sides are 15 cm each.

To Find :-

• What is the area of an isosceles triangle.

Formula Used :-

★ Area = ½ × Base × Height ★

Solution :-

Given :-

• Height = 15 cm
• Base = 15 cm

According to the question by using the formula we get,

⇒ Area = ½ × 15 × 15

⇒ Area = ½ × 225

➠ Area = 112.5 cm²

∴ The area of an isosceles triangle is 112.5 cm² .

✪ Extra Information ✪

✦ Isosceles Triangle :

• An isosceles triangle is a triangle with two congruent sides and congruent base angles.

✰ Properties of isosceles triangle :

• The unequal sides of an isosceles triangle is normally referred to as the base of the triangle.
• The base angles of isosceles triangle are always equal.
• The angles which is not congruent to the two congruent base is called an apex angle.
• The sum of three angle of an isosceles triangle is always 180°.