<apex:page lightningStylesheets="true" applyHtmlTag="true" >
    <apex:includeLightning />
    <apex:slds />

    <apex:form>
        <b>1st Approach</b><br/>

        <apex:selectRadio layout="PageDirection">
            <fieldset class="slds-form-element slds-form-element_compound">
                <div class="slds-form-element__control">
                    <div class="slds-form-element__row">
                        <div class="slds-size_1-of-2">
                            <div class="slds-form-element">
                                <div class="slds-form-element__control">
                                    <apex:selectOption itemValue="1" title="1st Radio button" itemLabel="test1"/>
                                </div>
                                <div class="slds-form-element__control">
                                    <apex:selectOption itemValue="2" title="1st Radio button" itemLabel="test2"/>
                                </div>

                            </div>
                        </div>
                        <div class="slds-size_1-of-2">
                            <div class="slds-form-element">
                                <div class="slds-form-element__control">
                                    <input type="text" id="input-01" class="slds-input" />
                                </div>
                                <div class="slds-form-element__control">
                                    <input type="text" id="input-02" class="slds-input" />
                                </div>
                            </div>
                        </div>
                    </div>
                </div>
            </fieldset>
        </apex:selectRadio>

        <br/><hr/><br/>

        <b>2nd Approach</b><br/>

        <apex:selectRadio layout="PageDirection">
            <div class="slds-grid">
                <div class="slds-col">
                    <apex:selectOption itemValue="3" itemLabel="option 3"/>
                </div>
                <div class="slds-col"><apex:inputText styleClass="slds-input"/></div>
            </div>
            <div class="slds-grid">
                <div class="slds-col">
                    <apex:selectOption itemValue="4" itemLabel="option 4"/>
                </div>
                <div class="slds-col"><apex:inputText styleClass="slds-input"/></div>
            </div>

        </apex:selectRadio>
    </apex:form>
</apex:page>