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# 2-92 homework help

## Body Mass Index (BMI)

Body mass index (BMI) is a calculation that uses height and weight to estimate how much body fat someone has. You can use the KidsHealth BMI calculator below to find your child’s BMI. But it’s also important to talk to your child’s doctor to help understand the results.

#### Tracking BMI

Starting when your child is 2 years old, the doctor will determine BMI at all routine checkups. Because BMI changes with age, doctors plot children’s BMI measurements on standard gender-specific growth charts. Over several visits, the doctor is able to track your child’s growth pattern.

Although not a perfect measure of body fat, BMI helps identify children who are gaining weight too slowly or too quickly.

#### What Do the Figures Mean?

BMI percentiles show how a child’s measurements compare with others the same gender and age. For example, if a child has a BMI in the 60th percentile, 60% of the kids of the same gender and age who were measured had a lower BMI.

BMI is not a direct measure of body fat. Kids can have a high BMI if they have a large frame or a lot of muscle, not excess fat. And a kid with a small frame may have a normal BMI but still can have too much body fat.

BMI is less accurate during puberty. It’s common for kids to gain weight quickly — and see their BMI go up — during puberty. Your doctor can help you figure out whether this weight gain is a normal part of development or whether it’s something to be concerned about.

The categories that describe a person’s weight are:

• Underweight: BMI is below the 5th percentile age, gender, and height.
• Healthy weight: BMI is equal to or greater than the 5th percentile and less than the 85th percentile for age, gender, and height.
• Overweight: BMI is at or above the 85th percentile but less than the 95th percentile for age, gender, and height.
• Obese: BMI is at or above the 95th percentile for age, gender, and height.

It’s important to look at the BMI as a trend instead of focusing on individual numbers. Any one measurement, taken out of context, can give you the wrong impression of your child’s growth.

While BMI is an important indicator of healthy growth and development, BMI is not a perfect measure of body fat. If you’re concerned that your child may be gaining or losing weight too fast, talk to your doctor.

## 2-92. Simplify each expression. Homework Help a. -32+|10+2| c. -5.37+8.14-1.89

(1)
Calculate the sum or difference: – 32 + ||
Calculate the absolute value: – 32 + 12
Calculate the sum or difference: – 20
(2)
Calculate the sum or difference: 2.77 – 1.89
Calculate the sum or difference: 0.88

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## Math Review of the Square Root Property

Math Review of the Square Root Property https://schooltutoring.com/help/wp-content/themes/movedo/images/empty/thumbnail.jpg 150 150 Deborah Deborah https://secure.gravatar.com/avatar/63fb4ad5c163b8f83de2f54371b9e040?s=96&d=mm&r=g June 30, 2014 December 2, 2014

#### Overview

The square root property is an important shortcut to use when solving quadratic equations, or any equation that asks for square roots and powers of 2. It uses the definition of a square root to solve for a variable.

#### Definition

The definition of the square root of a positive real number in symbol form is if x 2 = a, then x = ±√a. For example, the square root of 64 is ±8, because 8∙8 is 64 and -8∙-8 is also 64. Suppose that y 2 = b. Using substitution, y = ±√b. The variable b can stand for a positive real number, a monomial, or even a polynomial.

#### Using the Square Root Property with Positive Real Numbers

Suppose that x 2 = 100. Then x will equal ±√100, or 10 or -10. Suppose that y 2 + 11 = 92. Then y 2 = 92 – 11. If y 2 = 81, then y will equal ±√81, or 9 or -9. Suppose that x 2 = 49/25. Then x will equal √(49/25) or ±7/5.

Figure 1: The square root property holds with positive real numbers and variables.

#### Using the Square Root Property with Monomials

The square root property can also be used with monomials. Suppose the equation is 36x 4 y 2 = z 2 . Using the square root property, z equals √(36x 4 y 2 ) or 6x 2 y, because the square root of 36 is 6, the square root of x 4 is x 2 and the square root of y 2 is y. Similarly, if q 2 equals 20a 4 b 2 then q will equal 2 a 2 b√5. This is because the square root of 20 equals 2√5, the square root of a 4 is a 2 and the square root of b 2 is b.

Figure 2: The process of using the square root property with a monomial.

#### Using the Square Root Property with Quadratic Equations

Using the square root property can be a shortcut to solving perfect square trinomials. Suppose the equation is x 2 + 6x + 9 = 36. In this case, both sides are perfect squares, because the perfect square trinomial is (x +3) 2 = 6 2 . Therefore x + 3 = ±6. Solving for x + 3 = 6, x = 6 -3 or 3. Solving for x + 3 = -6, x = -6 – 3, or -9.

Figure 3: Using the square root property to solve a quadratic equation.