# IGCSE Mathematics Paper-1: Specimen Questions with Answers 134 - 136 of 324

## Question 134

### Write in Short

A square ABCD has two diagonals, O is center. Angle ODA = . Calculate angle OAD.

### Explanation

Here,

As we can see in the figure AC and BD are intersecting lines in square.

Angle ADO = , as we know angle made by intersecting of diagonal is so angle AOD =

Now, in any triangle addition of all angles will give

So, in

.

## Question 135

### Write in Short

In the diagram, and a line LM passing through point D. Angle . Find the angle LDB, CDM and ADL.

### Explanation

Here, and a line LM passing through point D.

Now, Angle is given.

• So, angles BDM and ADL are vertical angles as shown in figure, which will be always same.

So, angle

• Now, angles BDM and CDM are complimentary angles, as shown in figure.
• Two angles whose adding gives are called as complimentary angles.

So,

Now, , so .

So,

Thus, angle

## Question 136

### Write in Short

The diagram shows a regular pentagon and a square. Calculate the values of .

### Explanation

Here, pentagon is regular.

So, we can find it՚s exterior angle by using the formula , where n = number of sides.

In pentagon number of sides = 5, so exterior angle =

So, as shown in figure, its interior angle .

Now, for angle :

As shown in figure, total angle is , so

.

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