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3 years ago

I need help with these questions (see image). Please show workings.

Mathematics

2 answers:

Anton [14]3 years ago

5 0

Answer:

24 cm

Step-by-step explanation:

The chord, if the ends connected with the center, form an isosceles triangle with two sides being a radius of the circle.

Length of chord = x
Height of triangle = h = 5 cm
Radius = r = 26/2 = 13 cm

<u>From the triangle we get:</u>

(x/2)² + h² = r²
x²/4 + 5² = 13²
x²/4 = 144
x/2 = 12
x = 24

The length of the chord is 24 cm

denpristay [2]3 years ago

4 0

Answer:

24 cm

Step-by-step explanation:

The altitude from the centre to the chord is 5 cm and bisects the chord.

The radius of the circle is 26 cm ÷ 2 = 13 cm

There is a right triangle formed with legs 5 and x ( x is half the chord )

The hypotenuse is the radius, then using Pythagoras' identity

x² + 5² = 13²

x² + 25 = 169 ( subtract 25 from both sides )

x² = 144 ( take the square root of both sides )

x = $\sqrt{144}$ = 12

Then

length of chord = 2x = 2 × 12 = 24 cm

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If b/a=c/b=d/c=2/3, find the value of a:b:c:d

leva [86]

Answer:

the ratio would be 6.75:4.5:3:2

Step-by-step explanation:

replace d and c with

d=2 and c=3

Then using proportion multiplication, you will find that b is 4.5

now replace all b with 4.5.

Then again using proportion multiplication, you will get a is 6.75.

Plug in a, b, c, d in the ratio and you get 6.75:4.5:3:2

5 0

2 years ago

Show how u got the answer 309×42

luda_lava [24]

3
1
390
x 42
-------
1282
1564
----------------

the answer would be 16380
Hope this helped :)

4 0

3 years ago

Each car on a train has 200 seats how many seats are on a train with 8 cars

Sati [7]

Well it would be 200 × 8 which would equal to 1600

8 0

3 years ago

Read 2 more answers

A researcher reports survey results by stating that the standard error of the mean is 25 the population standard deviation is 40

bezimeni [28]

Answer:

a) A sample of 256 was used in this survey.

b) 45.14% probability that the point estimate was within ±15 of the population mean

Step-by-step explanation:

This question is solved using the normal probability distribution and the central limit theorem.

Normal probability distribution

When the distribution is normal, we use the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .