Question

The body mass index (BMI) is calculated as a person's weight (in pounds) times 720 , divided by the square of the person's height (in inches). A BMI in the range \(19-25,\) inclusive, is considered healthy. Write a program that calculates a person's BMI and prints a message telling whether they are above, within, or below the healthy range.

Short answer

Calculate BMI using the formula and print status relative to 19-25 range.

Step-by-step solution

Understand the BMI Formula

The Body Mass Index (BMI) is calculated using the formula: \( BMI = \frac{weight \, (lbs) \, \times \, 720}{height^2 \, (in^2)} \). This formula uses a person's weight and height to determine a numeric value that indicates if they are underweight, healthy, or overweight.

Define the Healthy Range

A BMI between 19 and 25 is considered healthy. The task is to determine where the BMI falls in relation to this range: below (BMI < 19), within (19 ≤ BMI ≤ 25), or above (BMI > 25).

Write a Program to Calculate BMI

Begin by creating a function or script that takes input: weight in pounds and height in inches. Use the BMI formula to calculate the BMI, \( BMI = \frac{weight \, \times \, 720}{height^2} \).

Determine and Print BMI Category

Use conditional statements to compare the calculated BMI with the healthy range values. If BMI < 19, print 'below healthy range'; if 19 ≤ BMI ≤ 25, print 'within healthy range'; if BMI > 25, print 'above healthy range.'

Key concepts

Understanding Conditional Statements in Python

Conditional statements in Python are fundamental for making decisions in a program's flow. They allow the program to execute certain sections of code based on whether a condition is true or false.
In Python, the most common conditional statement is the `if` statement, which can be followed by `elif` (short for else if) and `else` to handle multiple conditions. For example, when calculating BMI, you would check if the BMI value falls within specific ranges to determine and print whether the person is below, within, or above the healthy range.

• If condition: The program checks if the given condition is true. If it is, the indented block of code following the `if` statement is executed.
• Elif condition: Short for "else if", this allows you to check multiple expressions for TRUE. If the previous conditions were false, this condition is evaluated next.
• Else condition: If none of the preceding conditions is true, the block under `else` is executed.

With conditional statements, you can create a decision-making structure that matches the logic of real-world problems like BMI classification.

How to Use the BMI Formula for Calculation

The BMI formula is a straightforward equation that helps determine body mass index: \( BMI = \frac{weight \, (lbs) \, \times \, 720}{height^2 \, (in^2)} \).
To perform the calculation, you need two values: the person's weight in pounds and the height in inches. These values are inserted into the formula to yield the BMI, a number that can then be interpreted using the healthy range criteria.
The steps are as follows:

• Multiply the weight in pounds by 720.
• Square the height in inches.
• Divide your result from the first step by the result of the second step.

The BMI output serves as a quick estimate of whether someone is underweight, healthy, or overweight, and it's widely used in various health assessments.

Python Programming for Beginners: Crafting a Basic BMI Calculator

If you're new to Python, creating a BMI calculator is an excellent way to practice basic programming skills. You will learn how to gather input, perform calculations, and use conditionals to produce output. Here's a simple guide to start:
1. **Gather input:** Use the `input()` function to prompt users to enter their weight and height. Convert these inputs to integer data types for calculations.
2. **Calculate BMI:** Apply the BMI formula using the values you've gathered.
3. **Display Results:** Use conditional statements to compare the BMI result against the predefined healthy range and print the corresponding message.
By writing this simple program, you’ll cover several foundational topics in Python programming that are essential for more complex projects.

Evaluating Healthy Weight Range in Programming

In programming, evaluating whether a number like BMI falls within a specific range is essential for tasks like health assessments. This involves establishing boundaries and comparing values against them.
For BMI, a healthy weight range is defined between 19 and 25. Here's how you can evaluate the BMI value:

• Below Healthy Range: If the BMI is less than 19, it’s considered below the healthy range.
• Within Healthy Range: BMIs ranging from 19 to 25 are considered healthy.
• Above Healthy Range: If the BMI exceeds 25, it's classified as above the healthy range.

This concept is crucial when implementing logic that can assess and categorize data, allowing users to quickly identify areas that may require attention. It's a practical example of using conditional statements and ranges effectively in programming.