Four friends were born in consecutive years. The sum of their ages is 62.

I need help with these three problems please

Liono4ka [1.6K]

Answer:

Q7. 11.3 inches (3 s.f.)

Q8. 96.2 ft

Q9. 36.4cm

Step-by-step explanation:

Q7. Please see attached picture for full solution.

Q8. Let the length of a side of the square be x ft.

Applying Pythagoras' Theorem,

$34^{2} = {x}^{2} + {x}^{2} \\ 2 {x}^{2} = 1156 \\ {x}^{2} = 1156 \div 2 \\ {x}^{2} = 578 \\ x = \sqrt{578} \\$

Thus, the perimeter of the square is

$= 4( \sqrt{578} ) \\ = 96.2 ft\: \: \: (3 \: s.f.)$

Q9. Equilateral triangles have 3 equal sides and each interior angle is 60°.

Since the perimeter of the equilateral triangle is 126cm,

length of each side= 126÷3 = 42 cm

The green line drawn in picture 3 is the altitude of the triangle.

Let the altitude of the triangle be x cm.

sin 60°= $\frac{x}{42}$

$\frac{ \sqrt{3} }{2} = \frac{x}{42} \\ x = \frac{ \sqrt{3} }{2} \times 42 \\ x = 21 \sqrt{3} \\ x = 36.4$

(to 3 s.f.)

Therefore, the length of the altitude of the triangle is 36.4cm.

4 0

3 years ago

Read 2 more answers

What is the final amount if 1548 is increased by 5% followed by a further 6% increase?

stiv31 [10]

Answer:

1,718.28

Step-by-step explanation:

1,548, percentage increased by 11% (percent) of its value = 1,718.28

3 0

3 years ago

In a clinical test with 2161 subjects, 1214 showed improvement from the treatment. Find the margin of error for the 95% confiden

Vlad [161]

Answer:

The margin of error for the 95% confidence interval used to estimate the population proportion is of 0.0209.

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence level of $1-\alpha$ , we have the following confidence interval of proportions.

$\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}$

In which

z is the z-score that has a p-value of $1 - \frac{\alpha}{2}$ .

The margin of error is of:

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

In a clinical test with 2161 subjects, 1214 showed improvement from the treatment.

This means that $n = 2161, \pi = \frac{1214}{2161} = 0.5618$

95% confidence level

So $\alpha = 0.05$ , z is the value of Z that has a p-value of $1 - \frac{0.05}{2} = 0.975$ , so $Z = 1.96$ .

Margin of error:

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

$M = 1.96\sqrt{\frac{0.5618*0.4382}{2161}}$

$M = 0.0209$

The margin of error for the 95% confidence interval used to estimate the population proportion is of 0.0209.

4 0

3 years ago

The first term of a geometric sequence is equal to a and the common ratio of the sequence is r.

ololo11 [35]

Answer: (a) {a, ar, ar², ar³, ar⁴, ar⁵...}, (b) arⁿ⁻¹

For part (a), the question gives us the first term a, and then asks us to apply the common ratio r six times.

In order for ar = a, the nth term of r will have to equal 0 (this implies that n is an exponent; thus giving us the first term a, as r = 1).

Since we use this method on the first term, we must use it for the next five, in which r gains an additional exponent for every consecutive value (nth term) thereafter.

Ultimately getting: {a, ar, ar², ar³, ar⁴, ar⁵...}

For part (b), we first have to understand that the sequence does not start at 0, but at 1 for n. In order for ar = a, with n = 1, there needs to be subtraction of -1 within the exponent. So that arⁿ⁻¹

If we check and apply this, we can see that:

{ar¹⁻¹, ar²⁻¹, ar³⁻¹, ar⁴⁻¹, ar⁵⁻¹, ar⁶⁻¹...} = {a, ar, ar², ar³, ar⁴, ar⁵...} = arⁿ⁻¹ = Tn

4 0

3 years ago

Qué capital prestó Carlos a Miguel. Si realizó el préstamo a un tiempo de 200 días, al 15 % y el beneficio que obtuvo Carlos del

MrRa [10]

Answer:

I do not know how to read Spanish sorry........

Step-by-step explanation:

8 0

2 years ago