Question

tell me area of isosceles triangle ​

Answer 1

Answer:

Area of Isosceles Triangle=(b×h)/2 or b×h×(1/2).

Step-by-step explanation:

For example,

if the base is 2 cm and the height is 5 cm, then if you calculate it, you will get:

Area= (b×h)/2

Area= (2×5)/2 cm²

Area= 10/2 cm²

Area= 5 cm²

Answer 2

Answer:

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Step-by-step explanation:

Area of Isosceles Triangle Formula

Area = ½ × base × Height

• List of Formulas to Find Isosceles Triangle Area
• Formulas to Find Area of Isosceles Triangle
• Using base and Height A = ½ × b × h
• Using all three sides A = ½[√(a2 − b2 ⁄4) × b]
• Using the length of 2 sides and an angle between them A = ½ × b × c × sin(α)
• Using two angles and length between them A = [c2×sin(β)×sin(α)/ 2×sin(2π−α−β)]
• Area formula for an isosceles right triangle A = ½ × a2

The Altitude of an Isosceles Triangle = √(a2 − b2/4)

Area of Isosceles Triangle Using Only Sides = ½[√(a2 − b2 /4) × b]

b = base of the isosceles triangle

h = height of the isosceles triangle

a = length of the two equal sides

Example Questions

Question 1: Find the area of an isosceles triangle given b = 12 cm and h = 17 cm?

Solution:

Base of the triangle (b) = 12 cm

Height of the triangle (h) = 17 cm

Area of Isosceles Triangle = (1/2) × b × h

= (1/2) × 12 × 17

= 6 × 17

= 102 cm2

Question 2: Find the length of the base of an isosceles triangle whose area is 243 cm2, and the altitude of the triangle is 27 cm.

Solution:

Area of the triangle = A = 243 cm2

Height of the triangle (h) = 27 cm

The base of the triangle = b =?

Area of Isosceles Triangle = (1/2) × b × h

243 = (1/2) × b × 27

243 = (b×27)/2

b = (243×2)/27

b = 18 cm

Thus, the base of the triangle is 18 cm.

Question 3: Find the area, altitude and perimeter of an isosceles triangle given a = 5 cm (length of two equal sides), b = 9 cm (base).

Solution:

Given, a = 5 cm

b = 9 cm

Perimeter of an isosceles triangle

= 2a + b

= 2(5) + 9 cm

= 10 + 9 cm

= 19 cm

Altitude of an isosceles triangle

h = √(a2 − b2/4)

= √(52 − 92/4)

= √(25 − 81/4) cm

= √(25–81/4) cm

= √(25−20.25) cm

= √4.75 cm

h = 2.179 cm

Area of an isosceles triangle

= (b×h)/2

= (9×2.179)/2 cm²

= 19.611/2 cm²

A = 9.81 cm²

Question 4: Find the area, altitude and perimeter of an isosceles triangle given a = 12 cm, b = 7 cm.

Solution:

Given,

a = 12 cm

b = 7 cm

Perimeter of an isosceles triangle

= 2a + b

= 2(12) + 7 cm

= 24 + 7 cm

P = 31 cm

Altitude of an isosceles triangle

= √(a2 − b2⁄4)

= √(122−72/4) cm

= √(144−49/4) cm

= √(144−12.25) cm

= √131.75 cm

h = 11.478 cm

Area of an isosceles triangle

= (b×h)/2

= (7×11.478)/2 cm²

= 80.346/2 cm²

= 40.173 cm²