Question

1.Change the given sentence into passive voice: Why have they shut the door?
2.Change the given sentence into reported speech: He said to me," Are these boys naughty?"

Answer 1

Answer:

1) Answer. The passive voice for shut the door would be 'Let the door be shut'. In this sentence, 'shut' is the “past participle of the verb” shut and door is the object. This is an imperative sentence with an underlying instruction in an active form.

Answer 2

Answer:

$\orange{ \mathbb{ \large{ \huge{Hello}}}}$

${\huge{\sf{\blue{\underline {\underline{Question}}}}}}$

Find the area of a triangle, two sides of which are 18cm and 10cm and the perimeter is 42 cm :

Answer :-

Given that,

Two sides of triangle are 18 cm and 10 cm.

Perimeter of triangle is 42 cm

Let, third side of triangle be x .

So,

⟶ Perimeter = 18 + 10 + x

⟶ 42 = 28 + x

⟶ 42 - 28 = x

⟶ x = 14

Third side of triangle is 14 cm.

Now,

s = 42/2

s = 21

Semi-perimeter is 21 cm.

Area of traingle :

⟶ √21 × (21 -18)(21 -14)(21 - 10)

⟶ √21 × 3 × 7 × 11

⟶ √3 × 7 × 3 × 7 × 11

⟶ 3 × 7 √11

⟶ 21 × √11

Put √11 = 3.316

⟶ 21 ×3.316

$\longrightarrow \blue{\boxed{\bold{69.639}}\bigstar}$

★

Area of triangle is 69.636 cm²

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Formulas used:-

• Perimeter of triangle = Sum of all sides

• Heron's formula that is

Area of traingle = √s(s - a)(s - b)(s - c)

where,

s is semi-perimeter of triangle.

a, b and c are sides of triangle.

• Semi-perimeter = Perimeter of triangle/2