# IGCSE Mathematics Paper-1: Specimen Questions with Answers 90 - 93 of 175

## Question number: 90

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### Write in Short

A note of 10 rupees of India like a rectangle is having 137 mm of width and 63 mm of height. Calculate the area of the note.

[The area of a rectangle, width w, height h, is . ]

### Explanation

Here, note is having the shape like a rectangle with 137 mm of width and 63 mm of height.

We need to find the area of the note, so formula of a rectangle area: , which is given,

So, area of note =

## Question number: 91

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### Write in Short

The surface area of the Moon is 37 900 000 . Write this number in standard form.

### Explanation

Here,

(a) The surface area of the Moon is 37 900 000

So, standard from will be:

## Question number: 92

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### Write in Short

Factorize completely

### Explanation

Here,

• Factoring is the decomposition of an object into a product of other objects or factors, which gives the original equation when multiplied together.

So,

## Question number: 93

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Essay Question▾

### Describe in Detail

Diagram shows a triangle ABC and a rectangle ABDF. Angle and AB = 5 cm, AF = 9 cm and BC = 12.5 cm.

(a) (i) Write down the size of angle AEF.

(ii) Write down the size of angle BCA and EAF.

(b) Complete the statement: Triangle ABC is ________ to triangle AFE.

(c) AB = 5 cm, AF = 9 cm and BC = 12.5 cm. Calculate the length of EF.

### Explanation

(a) (i) Here, in angles BAC and AEF are alternate interior angles which will be similar.

So, .

(ii) For :

Here, both triangles are right-angled triangles, so

Now, in any triangle addition of all angles will be

So, in

So, in , will also be , as and are alternate interior angles.

(b) Here, Triangle ABC is similar to triangle AFE because there all three angles are same in both.

• Two triangles are called as congruent triangles when both have all equal sides and equal angles.
• Two triangles are called as similar triangles:

o If all angles are same in both.

o If all pairs of sides are in same proportion.

o If two pairs of sides are in same proportion and one angle is also same in both.

(c) Here, AB = 5 cm, AF = 9 cm and BC = 12.5 cm are given,

So, formula for similar triangles for side:

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