# IGCSE Mathematics Paper-1: Specimen Questions with Answers 36 - 38 of 175

## Question number: 36

### Describe in Detail

In the diagram, AB is a diameter of the circle, center O. DBE is the tangent at the point B. The line DCA cuts the circle at C. Angle BAC = .

(a) Write down the size of angle ACB.

(b) Calculate the size of angle CBA.

(c) Calculate the size of angle ADB.

### Explanation

Here,

(a) Angle BAC = is given,

- As we know, the triangle formed by the diameter and the inscribed angle (triangle ABC above) is always a right triangle.
- So, angle
**ACB =**

(b) Now, in triangle ABC,

(c) In triangle ABD,

So,

## Question number: 37

### Write in Short

The net of a solid is drawn accurately below.

Write down the special name for

(a) The squares shown on the net,

(b) The solid.

### Explanation

Here,

(a) The squares shown on the net are **equal squares,** which have equal lengths of edges.

(b) The solid of net image will called as **cube.**

- A cube is made by four equal squares which have six faces, eight vertices and twelve edges.

## Question number: 38

### Write in Short

The diagram shows a pole of length l centimeters.

(a) Mita says that l = 88.2. Round this to nearest whole number.

(b) If the pole has a length 86 cm, to the nearest centimeter. What can be said about l.

### Explanation

Here,

(a) Mita says that l = 88.2 cm.

So, for round this to the nearest whole number we need to see the digit after decimal point, if this digit is 5 or more than 5 then the digit before decimal point will increase by 1.

Here, the digit after decimal point is 2 which is less than 5, so digit 8 which is before decimal point will remain same.

So, length will be: **88** cm after rounding up.

(b) In fact the pole has a length 86 cm, to the nearest centimeter.

Then the nearest length can be:

(I) Less than 86 but more than 85.4: these all will round up and be 86 because digit after decimal point is 5 or more than 5.

(II) More than 86 can be: these all will also round up and be 86 because digit after decimal point is less than 5.