/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 19 Find the measure of the angle fo... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Find the measure of the angle formed by a clock's hands at \(10: 20 .\)

Short Answer

Expert verified
The angle formed by the clock's hands at 10:20 is 170 degrees.

Step by step solution

01

Identify the position of the hour hand

The hour hand on a clock at 10:20 is not exactly on the 10 but a little past it. Each hour mark represents 30 degrees (360 degrees/12 hours), and every minute, the hour hand moves 0.5 degrees (30 degrees/60 minutes). At 20 minutes past 10, the hour hand will be 10 hours plus an additional \ \(20 \times 0.5 = 10 \) degrees from the 10-hour mark. Therefore, the hour hand is at \ \(300 + 10 = 310 \) degrees.
02

Identify the position of the minute hand

The minute hand at 20 minutes is on the 4th mark since each mark represents 5 minutes. Each 5-minute mark is 30 degrees, so 20 minutes corresponds to \ \(20 \times 6 = 120 \) degrees.
03

Compute the angle between the two hands

Now, to find the angle between the two hands, subtract the smaller angle from the larger angle: \ \(310^\text{°} - 120^\text{°} = 190^\text{°}\). However, since the angle must be less than 180 degrees, we take the smaller angle formed by the clock hands: \ \(360^\text{°} - 190^\text{°} = 170^\text{°}\). Therefore, the smaller angle between the hour and minute hands at 10:20 is 170 degrees.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

angle calculation
Calculating angles between clock hands may seem tricky, but it follows a set of straightforward steps.
First, remember that a clock is a circle and there are 360 degrees in a circle.
To find the positions of the clock hands, understand that each hour mark represents 30 degrees \((\frac{360}{12})\).
For instance, at 10 o'clock, the hour hand is at 300 degrees (10 hours * 30 degrees).
However, as minutes pass, the hour hand moves slightly further in increments of 0.5 degrees per minute \((\frac{30}{60})\).
For 20 minutes past 10, that's an additional 10 degrees \(20 \times 0.5)\).
So, the hour hand at 10:20 is at 310 degrees.
Next, the minute hand moves 6 degrees for each minute \((\frac{360}{60})\); hence, at 20 minutes, it's at 120 degrees (20 * 6).
To find the angle between these hands, subtract the smaller angle from the larger one: \(310^\text{°} - 120^\text{°} = 190^\text{°}\).
If the result is more than 180 degrees, subtract it from 360 degrees to find the smaller angle: \(360^\text{°} - 190^\text{°} = 170^\text{°}\).
Thus, the angle between the hour and minute hands at 10:20 is 170 degrees.
geometry
Geometry plays a crucial role in understanding clock angles, as a clock face is essentially a circle.
A circle has 360 degrees, and each number on the clock represents a specific segment of those degrees.
The key is remembering that there are 12 hours on a clock and thus 30 degrees between each hour: \(\frac{360}{12}\).
Minute increments further divide the circle, where each minute moves the minute hand by 6 degrees \((\frac{360}{60})\), and the hour hand moves by 0.5 degrees \((\frac{30}{60})\) per minute.
Understanding these divisions helps in accurately determining where the hands are and calculating the angle between them.
It's simply a matter of applying basic arithmetic within these consistent geometric principles.
This makes learning clock angles a valuable exercise in applying geometric concepts.
clock angles
Understanding clock angles is a practical application of geometric principles.
To grasp clock angles, remember these key points:
  • A full clock rotation is 360 degrees.
  • Each hour mark on a clock is separated by 30 degrees \((\frac{360}{12})\).
  • The minute hand moves 6 degrees each minute \((\frac{360}{60})\).
  • The hour hand moves 0.5 degrees every minute \((\frac{30}{60})\).
These steps simplify the process.
At any given time, like 10:20, you calculate the precise positions by converting hours and minutes into their corresponding degrees.
This understanding allows you to compute the angle by straightforward subtraction, ensuring you find the smallest angle possible if the result exceeds 180 degrees.
By recognizing these divisions and conversions, calculating clock angles becomes an easy and enjoyable application of basic geometry concepts.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Round answers to the nearest unit. You may use 3.14 as an approximate value of \(\pi .\) If you have a \(\pi\) button on your calculator, use that value and then round your final answer. If the front tire of this motorcycle has a diameter of \(50 \mathrm{cm}(0.5 \mathrm{m}),\) how many revolutions will it make if it is pushed \(1 \mathrm{km}\) to the nearest gas station? In other words, how many circumferences of the circle are there in 1000 meters? (PICTURE CANT COPY)

Angular velocity is a measure of the rate at which an object revolves around an axis, and can be expressed in degrees per second. Suppose a carousel horse completes a revolution in 20 seconds. What is its angular velocity? Would another horse on the carousel have a different angular velocity? Why or why not?

Developing Proof In Exercises \(1-4,\) the four conjectures are consequences of the Inscribed Angle Conjecture. Prove each conjecture by writing a paragraph proof or a flowchart proof. Use reasoning strategies, such as think backwards, apply previous conjectures and definitions, and break a problem into parts to develop your proofs. The opposite angles of a cyclic quadrilateral are supplementary. Given: Circle \(O\) with inscribed quadrilateral \(L I C Y\) Show: \(\angle L\) and \(\angle C\) are supplementary (GRAPH CANT COPY)

Each year a growing tree adds a new ring to its cross section. Some years the ring is thicker than others. Why do you suppose this happens? Suppose the average thickness of growth rings in the Flintstones National Forest is \(0.5 \mathrm{cm} .\) About how old is "Old Fred," a famous tree in the forest, if its circumference measures \(766 \mathrm{cm} ?\) (IMAGE CAN'T COPY)

If a trapezoid is inscribed within a circle, then the trapezoid is isosceles. Given: Circle \(R\) with inscribed trapezoid \(G A T E\) Show: \(G A T E\) is an isosceles trapezoid (GRAPH CANT COPY)

See all solutions

Recommended explanations on Math Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.